Things to tell if the car was really "Garage kept"
1. The paint [usually the roof & top of the trunk] is weathering, or fading out [not chipping off] and faded so much that it has turned white from some places. This will usually happen in one circle then the circle grows. I'll be more than happy to show examples.
2. The leather is deteriating from places that are not used. For instants, the top back of the back seat [near the speakers] you will see hard wrinkles or if worse colonies of cracks.
Also, look under the car and observe it so see any rust. Always inspect the muffler to see a whole or rust. Ask a person to press the gas pedal all the way down and in the back the muffler should throw out a lot of Air [don't put your face or nose front of it, or you are going to get smacked by air or some hot oil might splatter out. If it doesn't then mostly likely the pipes some where are damaged.
For example: I was checking a 1994 Honda Accord with 14,xxx miles last year. Owned by a very old lady since 1994. For $9k, got sold for 8,800. Anyways, the muffler had a real big whole in the bottom, if I was serious I would have taken it to a mechanic and had it lifted to see for further rust. But everything else was brand new, except for some scratches.
I also didn't buy the car, because I don't drive a lot. So, 14k miles was not that important to me. I was looking for a car for show [high school] it was a 1994, nobody is going to know how many miles it has on it and that I paid $9k and not $3-4k.
This works great the other way around, buy a new model with high miles; are you going to know how many miles it has on it? NO.