How often should you check your investment portfolio?
- Robin Powell
- 1 hour ago
- 9 min read
Most investors think the hard part of long-term investing is choosing the right funds. It isn't. The hard part is deciding how often you let yourself look at what those funds are doing. How often should you check your investment portfolio? Probably far less often than you do.
It's early evening on a weekday. You're not doing anything in particular. The phone is on the arm of the sofa. You pick it up, open your platform, and look at the number. The market closed an hour ago. Nothing you see can change anything you'll do. You look anyway.
The specifics vary. For some readers it's the SIPP on Hargreaves Lansdown at the kitchen table; for others it's the Vanguard app on the morning train, or a refresh of the ISA balance after the Today programme mentions a wobble on Wall Street. The pattern is the same. A long-horizon portfolio meeting a short-horizon habit, several times a week, for no good reason and to no useful end.
It isn't just you. The smartphone has done to investing what slot machines did to gambling — taken a long-horizon activity and given it a short-horizon interface, complete with red lights, percentage badges and live price feeds. The behaviour is universal. The problem isn't willpower. And the question almost every retail investor asks themselves and almost nobody asks out loud — how often should I check my investment portfolio? — has a real, evidence-based answer.
The maths guarantees you feel terrible
Check your portfolio every day and the maths of the stock market is rigged to make you miserable.
In his new book Risk & Reward, Ben Carlson does the arithmetic. Looking at the S&P 500 from 1950 to 2024, he reports that the market is up on 56 per cent of trading days and down on the other 44 per cent. On any given day, the market is barely better than a coin flip.
Now layer in what behavioural science has known for more than 30 years. Losses don't just feel bad. They feel roughly twice as bad as equivalent gains feel good. The empirical loss-aversion coefficient — first measured by Amos Tversky and Daniel Kahneman in their 1992 prospect-theory paper, and replicated many times since — comes out at around two.
The arithmetic isn't subtle. If a green day gives you one unit of pleasure and a red day gives you two units of pain, your average daily emotional return on a portfolio that's quietly rising over time is still negative. You can be making money and feel like you're losing it. That isn't a quirk of your psychology. It's everyone's psychology, applied to the wrong time-frame.
Andre Agassi, of all people, put it more cleanly than any academic. In his memoir Open, quoted by Carlson, he writes: 'A win doesn't feel as good as a loss feels bad, and the good feeling doesn't last as long as the bad. Not even close.' He was talking about tennis. The mechanism is the same.
This is the slot machine again. A modern fruit machine pays out just often enough to keep you pulling the lever, and stings just often enough to keep you anxious. A 56/44 daily market split is doing something similar to anyone who keeps the app open. Just enough wins to keep you watching. Just enough losses to keep you tense.
The long term is not where life is lived
Daniel Kahneman gave this phenomenon a name, and won a Nobel Prize for explaining why it costs investors money.
In his Nobel acceptance speech, Kahneman delivered the line that ought to hang above every investor's desk: 'the long term is not where life is lived.' The financial planner can draw you the world's most beautiful 30-year growth chart. Your nervous system will still respond to today's red number on today's app. Emotion is triggered by change, not by totals.
The academic case is older still. Working with Richard Thaler in 1995, Shlomo Benartzi coined the term myopic loss aversion to describe what happens when loss aversion meets the human tendency to evaluate outcomes too often. Their paper in the Quarterly Journal of Economics — itself an attempt to solve the equity premium puzzle — argued that investors demand such a large premium to hold stocks over bonds partly because they evaluate their portfolios too frequently to enjoy them.
Two years later, Thaler joined Amos Tversky, Kahneman and Alan Schwartz to test the prediction in a controlled experiment. The result is the single most useful sentence in this whole literature: 'The investors who got the most frequent feedback (and thus the most information) took the least risk and earned the least money.'
Read that line again. More information, less return. The participants who looked the least did the best.
The literature has known this for three decades. The advice — check less often — is at least as old. What's new is the delivery mechanism. Thirty years ago, telling people not to look at their portfolio meant telling them not to open the broker's paper statement when it arrived in the post. Today it means asking them to ignore the most carefully engineered notification system ever built, sitting in their pocket, pinging.
What happens when you zoom out
Stretch the holding period from days to decades and the picture inverts completely.
Carlson runs the numbers in Risk & Reward for that same S&P 500 series. The probability of being down a year after you bought is around 19 per cent. Over three years it falls to roughly one in ten. Over five years, one in twenty. Over 10 years, on his data set, none. Over 20 years, none. The figures are US-only — and past performance is not a forecast — but the shape of the curve is what matters. Time is the one factor that systematically converts the market's daily anxiety into long-term wealth.
Carlson illustrates the same point with a thought experiment he first published on his blog in 2014, and revisits in the new book. He calls it Bob, the world's worst market timer. Bob is the hypothetical retirement saver who only ever invests at market peaks. He puts $6,000 in just before the 1973 crash, $46,000 just before 1987, $68,000 just before the dot-com bust, $64,000 just before the 2008 financial crisis. He saves $184,000 in total over 40-plus years and times every single lump sum disastrously.
He retires a millionaire. $1.1 million, to be exact. Because he never sells. Time does the work.
Note what Bob doesn't have. He doesn't have a smartphone. He doesn't have a sell button he can hit at 7am from the bathroom. His success is, in part, the success of someone who couldn't easily ruin it.
But what about Japan?
The strongest counter-argument to long-term equity investing is Japan, and it doesn't break this article's central point — it sharpens it.
The Nikkei 225 peaked on 29 December 1989, just below 39,000. It didn't reclaim that level until February 2024. Three decades and change of going nowhere. Carlson is honest about this in the introduction to Risk & Reward, noting that 'Now show Japan!' is the standard objection to any argument that runs 'just hold for the long run'. He calls it a fair criticism.
It is. An investor who held only Japanese equities through that period would not have been rescued by time. The maths didn't bail them out.
But notice what would have bailed them out. A globally diversified equity portfolio over the same decades performed perfectly well. The Japanese investor who lost out wasn't the one who picked the wrong country and held on grimly. It was the investor who panicked partway through, sold at a loss, and locked in the disappointment that time might otherwise have softened. That's a checking-frequency problem dressed up as a stock-market problem. Lose faith in your strategy because of what you saw on the screen this morning, and the screen wins.
So the optimistic case (Bob) and the pessimistic case (Japan) point at the same lever. It isn't whether you pick US equities or Japanese ones. It isn't even, particularly, whether you pick stocks or bonds. It's whether you can keep your attention away from the daily price screen long enough to let the strategy work.
Why willpower won't save you
Knowing all of this changes nothing if your phone still buzzes the moment the market opens.
The behavioural finance literature is a generation old. The advice 'don't check your portfolio so often' has been quietly available for the whole of that period. And yet UK retail investors are checking more often now than at almost any point in financial history. The body of evidence isn't getting smaller. The behaviour is getting worse.
That gap tells you something important about the nature of the problem. 'Check less often' is a willpower instruction. It's being delivered into a willpower-hostile environment. You can read every behavioural-finance paper ever published and still find yourself thumbing the app at the bus stop. You aren't weak. The interface is strong.
Think about who designs investment apps, and how. Real-time prices. Red and green colour coding. Push notifications when your watchlist moves. Percentage-change badges. Daily summary emails. Pull-to-refresh, the same gesture that loads new posts on Instagram. None of these features are neutral. They are engagement mechanics borrowed from social media and gambling, then applied to the longest-time-horizon activity most people will ever undertake.
So when you ask yourself how often you should check your investment portfolio, the honest answer is that the frequency isn't really the problem. The environment is. Nobody beats a casino by sitting at the table longer and trying to be more disciplined. You beat it by being somewhere else. The only solution that works is the one that doesn't require willpower.
How often should you check your investment portfolio — and what to do instead
The answer is this: design your environment so the question rarely comes up.
A short set of moves, all evidence-based, none of them requiring you to become a calmer or more disciplined person than you were yesterday.
First, set a cadence. Quarterly is enough for almost any investor still in the accumulation phase. Annually is enough for many. The point isn't the precise number; it's that you've decided in advance, calendared it, and turned a habit into an appointment. A scheduled check is psychologically different from a compulsive one, even when the underlying data is identical.
Second, delete the app from your phone. Not 'turn off notifications', not 'move it to the second screen' — delete it. If you need to check, do it deliberately, from a desktop browser, having made a small effort. Friction is the entire point. The Thaler experiment found that less frequent feedback led to more risk-taking and higher returns. Friction is how you give yourself less frequent feedback in a world that's trying to give you more.
Third, change the question you ask. Stop asking 'how is my portfolio doing?' Start asking 'am I on track for my goals?' The first question can only be answered with a price. The second can be answered with a plan. One belongs to the market; the other belongs to you.
Fourth, replace performance-watching with savings-watching. The variable you actually control is the amount you put in each month. The variable the app shows you is the one you don't control. Watch the thing you can move.
None of these is a discipline upgrade. Each is an architecture change. Change the room, not the resident.
The investor who looks least
The hardest part of long-term investing isn't understanding it. It's surviving it.
Go back to where this piece started — the phone on the arm of the sofa, the number on the screen, the look that changed nothing and cost you something anyway. The deeper question hiding inside 'how often should I check my investment portfolio?' is this: how much of your emotional life are you willing to hand over to a number that, on most days, exists only to make you feel something you'd rather not feel?
Carlson's Bob succeeded because his attention couldn't keep up with his portfolio. Yours can, every minute of every day, and that's the problem the previous generation of investors didn't have to solve. They were rescued by the inconvenience of paper statements. You have to rescue yourself by designing the inconvenience back in.
The investor who looks least, in the end, usually wins most. Not because they care less than you do. Because they've designed a life in which their portfolio doesn't need their attention to do its job.
Resources
Benartzi, S., & Thaler, R. H. (1995). Myopic loss aversion and the equity premium puzzle. Quarterly Journal of Economics, 110(1), 73–92.
Kahneman, D. (2003). Maps of bounded rationality: A perspective on intuitive judgment and choice. Nobel Prize Lecture, December 8, 2002. American Economic Review, 93(5), 1449–1475.
Thaler, R. H., Tversky, A., Kahneman, D., & Schwartz, A. (1997). The effect of myopia and loss aversion on risk taking: An experimental test. Quarterly Journal of Economics, 112(2), 647–661.
Tversky, A., & Kahneman, D. (1992). Advances in prospect theory: Cumulative representation of uncertainty. Journal of Risk and Uncertainty, 5(4), 297–323.
Where to go from here
Ben Carlson's Risk & Reward: How to handle volatility and uncertainty for the long-term investor is published by Harriman House. It's available direct from the publisher and on Amazon UK.
If the behavioural side of this piece resonated, the underlying principles run through How to Fund the Life You Want by Robin Powell and Jonathan Hollow. The second edition, published by Bloomsbury, sets out a practical, evidence-based approach to building a financial plan that suits the way real human beings actually behave around money. Available on Amazon.
If you'd rather work with someone who already thinks this way, our Find an adviser directory lists firms that have publicly committed to low-cost, globally diversified, evidence-based investing.
