Suppose you had a permanently young body (you get to pick an age; maybe somewhere between 25 and 35) and also permanently fit and healthy body - you never die or get a terminal illness, and major injuries always eventually recover so you never become blind or paralyzed (although you do still suffer a lot of pain, so it’s not like you’ve been gifted Superman-like invincibility.)
You still have to work for your income. You still have to do all the things normal people have to do to get by.
Under such circumstances, how long do you think you could live before “life fatigue” starts to kick in and you think, “All right, I’ve had it, don’t want to live anymore?” A thousand years, ten thousand, a million years?
Maybe when you have seen the same face in the mirror a million mornings in a row? Or when you have outlived twenty spouses’ lifetimes and had a hundred children?