It's best to follow your doctor's guidelines. Your age and overall health make a difference. The amount of disease present in your other knee is also a factor. Wear and tear on the new implant can be affected by increased load when the other knee doesn't carry its fair share.
The type of implant used will also dictate how often you see the doctor. Early detection of problems like cracking, loosening, or uneven wear can save the implant and keep you from having major surgery again. Since the average joint implant lasts 10 to 15 years, it's reasonable to have your doctor follow you throughout that time.