Unless you have a serious crash or the most common bike accident, which is going into the garage with your bike on the roof rack of your car, your bike rims will probably last as long as you can stand riding the same old bike. Rims are usually made of aluminium. They are light and strong, and they almost never cause problems on a bike, even when riding is hard.
In fact, I bet most people who ride bikes never even think about their rims. It's easy to forget about the round metal band that holds the tyre in place and connects it to the wheel hub with spokes. A bicycle rim doesn't break as often as the spokes do. Unlike the hub, it doesn't cause problems very often. Unlike tyres, it never goes flat or explodes. Serious bike racers have fancy rims with the same crazy, bright ads that are usually all over their clothes, but most riders don't really need these. Even the most expensive wheels, which have flattened, wide, and presumably aerodynamic rims, are probably not that much better. They are, however, flashier, which seems to mean something in the world of cycling, maybe to scare people away.
Should you know anything special about your bike's wheels? Actually, no. Most bicycles come with rims that match the quality of the bike as a whole. You can spend as much money as you want on rims and anything else related to cycling, but the ones that come with a bike are probably fine. Customizing your rims will give you fancier, maybe lighter, and probably stronger rims, but research on the best rim weight, strength, and shape is still mostly inconclusive. Since this feature doesn't cause many problems for recreational riders, you can leave this to a professional mechanic who works on the bikes of world-class racers. When they have fixed the problem, they will let you know.
Most bicycle rims today are made of aluminium because steel rims are heavy and carbon rims are expensive. Aluminum rims don't need much care. As with the rest of your bike, the rims should be kept clean and free of dirt and oils that can damage them. They should also be wiped down after long, dusty rides and looked at after a crash. If not, do what most cyclists have always done and forget about your bike's rims. You might not be able to ride a bike without them, but you won't be able to ride a bike better if you think about this important but otherwise unimportant part.
