RE: How old is your bow?
My oldest was made in '64. Newest was made in 2003.
There isn't any set age or number of arrows that tells you when to replace a bow. A lot of it has to do with how much the bow has been mistreated by shooting overly light arrows. Any bow that's used to shoot minimum weight arrows is going to wear out a lot faster than one that's been used with heavier arrows.
I've got compounds from the 80's that are still in perfect shooting condition because they've never shot any arrow less than 8 grains per pound.