Good luck tc my friend, one of my Vietnam-era friends had both knees replaced a couple of years ago. It all worked out well for him and he’s pretty much back in form.
And congrats on retirement, I retired early 7 years ago and life is good. I miss the people and the intellectual challenge of what I did, but not the business environment. There’s a lot of advice about retirement but the only good advice I can give you is to get into a regular exercise routine - that’s important as we get older.
Cheers, Steve