I had a house with a 58 year old Lennox furnace.
It worked flawlessly.
I’ll never buy anything else.
I agree 100% with the longevity of older appliances. One thing, though is if you do your homework, newer appliances can be efficient enough to save more money on energy costs even if they last only 10 years. Which is the warranty length of my variable speed heat pump and hybrid water heater, which do wonders in the warm Alabama climate.