If the rim simply has a gentle warp like a potato chip, it might be possible to use it again. If it is dented, bulged, or other wise sharply bent, it is probably not re-usable.

Bicycle wheels are pretty strong. Sure, some are stronger than others. But the problem is most likely how you are using them.

Maybe you can provide more information. What brand rims, what size rims (26", 700C, etc), and what size tires (26x1.5", 700Cx25, etc)? What inflation pressure? What do you mean by bad roads - are you riding through deep potholes, riding off curbs, what? How much do you weigh?