RE: How old is too old for a bow.
It's hard to say--depends on how it's been treated over the years, how good the materials were to begin with, how much it's been shot, etc. etc. etc. I know of (and have owned) lots of old bows that shot great, and still shoot great--and I've seen a few that delaminated for no apparent reason. Sometimes they just give it up--my opinion is it's better to put them to use than to have them hang around and gather dust.
Chad