The best age to retire his probably when you feel that your skills officer I will fill it are starting to slip and that you are starting to lose track of your work or such. There are many companies in my country where the retirement age is set between 55 and 60 for people. There are cases where people work to an older age, and this is by choice of course. I think that it all depends on the person as well and how they are financially planned and so forth. Some work to keep themselves busy past retirement and some work for financial reasons.