Mine took more than their share of beatings and abuse.
Couple of 'scopes' on one knee which made it worse. Tried all the internet voo-doo supplements. Cortisone a couple of times. Draining big quantities of water out of one a couple of time and the Doc said "it's time" to replace.
At about your age my activity level decreased very rapidly. Going up stairs a real challenge...going down without a handrail was not going to happen. Drop car keys in parking lot--not good at all. Lots of other aches and pains came with the bad knees due to favoring the knees....hips and ankles not good--pain gone after replacement.
Not quite two years ago had both knees replaced. Both very successful outcome. Kinda like the clock got rolled back 20 years. Some limitations but very very minor. About 3 months between the two replacements. In on a Monday at 7AM....home the next day at 4PM. Recovery can be challenging but not bad.
Medicare coverage was great.
You might not be at that point yet but get a couple of opinions.