Spending from  a 20 btc stash is okay if you are over 70 and have other income. One coin a year till you are ninety or .85 coin a year spending those amounts either way should work.

Especially if you don’t care about descendants.

Spending from a 20 btc stash if you are under 50 needs to be very small spends under 0.5 a year would be good.