I also have a Legacy, and I waited about 4 years before I changed them, Probably too long. The reason I changed them was because they stretched far enough to put the Bow out of spec. and even after twisting them to bring it back into specs I lost about 4-5 lbs of draw weight. I think it depends on how much you shoot, and of course if you keep it wax good. Some say change them once a year, I think maybe every two years. On an old string/cable it might look ok, but could have some damage inside that you can't see. Better to be safe... Your Legacy is what 5 or 6 years old?