Time to replace shocks?

I've never kept a car as long as I have the Dart GT (it will be 14 years in August). The car is driven ~1,000 miles per summer. Will the shocks "wear out" spending most of it's life parked in the garage? What wears out a shock (mileage or time)? The car is an ice cream parlor cruiser, so what we be a good replacement shock (if needed)? As always, any advice is appreciated.