My husband and I both had both knees replaced while we were in our 70's. Prior to those surgeries, we experienced quite a bit of pain, and my gait and appearance of my legs had been badly impacted. For each of us, one knee was more troublesome than the other, and we had it done first. We had great physical therapists who guided us through a helpful rehab regimen. We had heard from several sources that without conscientious physical therapy one might as well not have the surgery. With the great success of the first, we chose to schedule the other one about 4 months after the first. The difference in how we feel is fantastic. Those surgeries were about 10 years ago, and we continue to be pain free. We don't play tennis anymore due to other issues, but we never get tired walking on hikes or taking care of things around the house.