Buster has 3/4 LP in both his back legs. He had the surgery on the one that was causing him issues, the Orthopedic Surgeon said to wait on the other leg until it was causing him pain/problems. He was unhappy with being crated during the recovery time but it was worth it. I would be careful about choosing someone to perform the surgery just because they are cheaper. Look into how many times they have performed this surgery especially on small dogs. For me going with an Orthopedic surgeon was the wiser choice. I did not want Buster to be in pain. It is not just the limping when they are in pain he would lift the leg bothering him when standing as weight bearing on it caused him pain.
The reason to do it earlier rather than later is that the more they use the leg the more damage is caused to the joints which results in irreversible damages which causes arthritis later on in life. Also by running off kilter they can cause damage to other ligaments.