Rebalancing is the least glamorous work in investing. It produces no stories and no conviction trades. It also forces the right behaviour: selling a little of what has run up and buying a little of what has lagged.
Left alone, every portfolio drifts toward whatever has recently done well. That feels pleasant right up until your risk sits exactly where prices are most stretched. Drift is how a careful allocation quietly becomes a bet nobody chose.
The discipline matters more than the calendar. Annually or by threshold, the point is that the decision is mechanical, made in advance and executed without a view on where markets go next.
It will regularly feel wrong. Trimming winners always does. Over decades the payoff shows up less in returns than in risk that stayed the size you agreed to.