Why wouldn't you be able to? Unless you age really badly you should still be just fine. Maybe at 90 you will just be too tired, but unless you get a brain disease or some other kind of dementia you will still be the same as you are now. Al lot of people work at 70 or older, it's recommended that you work until 70 before you collect social security if your retirement funds are lacking. You young kids think anything over 45 is ancient, well it's not, and 70 is "young" old age, and people are still perfectly capable.