How long should you own a bow until you buy a new one. Or, how many years until a bow is obsolete?

You should own a bow as long as you want.

A bow is obsolete only when you buy a new piece of equipment and it won't fit on your bow.

None of the animals I have killed where ever concerned about how old the bow was.

There's no time table on owning a bow. A new bow today seems to be obsolete the next year with all the new innovations. The animals don't know what bow your sporting. When you feel it's time to upgrade, just do it. Seems I get the ergeevery 4-5 years or so.

keep it till you want a new one