That is something that should not have to be done for many thousands of mile sunless there is another issue
Wheel bearings are designed to last around 100,000 miles give or take. It is not uncommon to have them last as long as the car. Normally, if your mechanic is good and thorough, they will be inspected every time you get a brake job (approximately every 35-50,000 miles) and re-packed with grease if necessary at little or no cost.
