Oldest a used car should be bought?

I plan to buy a car (used) in the near future. I primarily wanted to buy a Ford Escape Hybrid 2012 but will probably switch to an all gas SUV (because I LOVE SUV). What's the oldest a used car should be?

Added (1). WHen I say old I mean how many years the car has been in use.

My girlfriends dad daily drives a 79 bronco

Mine is a 94 model.

Really is a pretty stupid question.

Don't buy anything over 3 years old and over 60,000 miles.
You can try looking at a Subaru XV Crosstrek. It's there SUV type car and is also offered with a hybrid engine.