I think most people that feel good at one year are unlikely to have a serious problem that second year, but that is just my opinion from a statistical point of view and the people I know with tkr's (not a medical opinion or specific to you). In my case, just over a year, I have enough lingering problems that I'm preparing for the possibility of more medical expenses and time in my upcoming year. I still have the warmth, and a couple pain spots that I'm trying to deal with via PT rather than risk arthroscopic surgery.
I admit to being wary of Murphy's law. In this context, if I reduced my insurance, I might be more likely to have a health problem. Therefore I'd pay for more, and not have to use it.