Apple grossly marks up extra disk and memory, and it's painful.

My strategy is to get the smallest internal disk I can - because a lot of things stay in the cloud, and the really big files live on external disks anyway. I do not pay for a faster CPU because I am almost never CPU-bound.

But I do max out on RAM, because that's very hard or often impossible to increase, and because that is the one resource I do sometimes run out of, and then everything gets sooooo sloooooooow.

I plan to get one of the next M1 laptops - this old machine is still serving my needs, but realistically it will have to be replaced in the next couple of years - and I'm excited!