You may try to take this way of taking profits just as how DCA happens. You can start taking 10% of your whole portfolio for profits if you are ever in need of money. But if not, do the math for yourself and what's comfortable and convenient to you. What I suggest is don't sell all that you have specially if the holdings that you have are the likes of BTC and ETH. They're hard to repurchase and that's why you need to be wise when you're going to sell them. Make sure that you have other plans of whether recovering them back or DCAing style again for it.
10 percent can be small or too much, so we will also need to check the circumstances here, but it's great that you clear that your point is mostly to not sell all what we have, but unfortunately for those who only have a small investment, maybe they will still need to sell all if they think their spendings are also expensive.
It is not that coins like BTC and ETH are hard to re-purchase/purchase, I mean because we can still buy them at a smaller portions. We can rather say that it will now be hard for us to see them at a cheaper value again as the time passes by. It is always better to have an investment, so yeah that it is also a must to recover them back.