With a bow getting only about 500 hundred shots a year (that's a month for me) and properly cared for the limbs themselves would last almost indefinitely. They would lose a few pounds over about 10 years, but nothing drastic.

I've had bows that only lost a couple pounds sitting around for 20 years, and that was one with older wood.glass laminated limbs.

Most limb material is impervious to most anything except extreme heat. Shooting them doesn't hurt them. That's what they are made for.

Believe me, if you take care of your bow you can't shoot enough or keep it long enough to tell any difference in performance.