Your cars wheel bearings should last for 100,000 miles or more. But like all things they will eventually wear out and need replaced.
Some wheel bearings can go longer than 100,000 miles but others will need replacing at 100,000 miles.
When your wheel bearings are starting to go bad you should hear a grinding type noise and the noise should increase the faster you go.
If you start hearing a grinding noise or a roaring type noise coming from your car when you accelerate you should take your car into a mechanic and have them check it out.