If you bash them, look for cracking or disforming. If they crack from age, replace with stock if you want. If they crack or disform from heavy usage, upgrade. If you lift your vehicle make sure you space your bumps so you dont bottom out your shocks. Same goes for using your shocks to limit travel. In that case, limit straps are needed.
I have seen quite a few shocks ruined due to not setting both ends of travel correctly.
Timbren stops are a good upgrade.
If you have a small trailer heres another idea. The rear of my Cruiser, I use Poly Airbags. They don't limit my travel more then I like when their low pressure and they increase my spring rate when I pull my trailer. I have also abused the crap out of them without issue.