I got a 1967 Cadillac that basically sat from 1974 to 2004 (30 years).
My grandma started it up once in a while and pumped the brakes. It drove under its own power onto the transport when it came down to stay with me in 2004. I let sit months without even looking at it and it has been doing fine for the past 8 years.
Batery disconnect switch FTW!
Interesting fact in the 46 years it has been around it has driven less than 1,200 miles a year.Not a high use vehicle.