I normally withdraw enough for the year in mid January, early February, selling from the winners to fund the year, then selling more to achieve rebalancing. I also have at least 5% cash but ideally at least 10% cash, which can fund at least 2&1/2 years of spend.
However when the market goes to the moon, I often do early sales to build cash; the most was about 18 or 19%. In COVID and 2022, the extra cash allowed some purchases at nice low prices, including PDI, PRU, CMI, and mutual funds. I did a bit of early extra selling last year, diverting mostly to income but also to cash.
Cash is not trash, particularly when markets are looking stretched. Booking gains before they can disappear (in the blink of an eye) is a form of risk protection, particularly early in retirement or before early retirement, when most of our highest % withdrawals will occur, before SS and/or pensions kick in.
Of course, as some will tell you, you probably will not maximize portfolio gains,--stretched markets can continue to stretch, for years.....until the rubber band breaks and those wonderful awesome gains disappear, often quite suddenly.