75 is a solid life if it is well lived and you are able to take care of yourself (physically, mentally, financially) up until the end. Anything after that is icing on the cake, I think. I am amazed when I hear of people in their 80s and 90s who go in for serious surgical procedures (broken hip, bypass, etc). When you go in for a procedure like that you've got to be thinking "this is the end" cause so many things can go wrong when you're that age that can kill you. But some of them make it out of surgery and go on to live 5 -10 more years! Amazing!
My grandfather is going on 94 and he fell off his neighbors roof 2 years ago and broke his hip (he was roofing his neighbors house for him).
He still gets up every morning, mows the pasture, feeds the cows, and works all day.
He also has no TV, no cell phone, just a land line and a radio. He thinks computers are the mark of the beast.
And he's still going strong. Lol.