Some other obvious clues buying vehicles are the ones that looked like people have lived inside them. I have gone to look at modern cars that had not even been cleaned. Washing is one thing, but filthy is another. Burger wrappers, soda and coffee spilled, trash, child seats in with food spilled, ashtrays full, improvised repairs made like taping a mirror back on, windshields scraped by worn out wiper blades and so on. I am sure you get the idea.
Looking under the hood, you see acid built up on a battery, a dip stick that shows dirty oil, and leaves packed in the air cleaner. I always wonder why a vehicle is being sold; I am wary. If you don't mind this and offer a low, low price, it's some clues about the condition. However I have driven to deplorable homes and found very desirable models and motorcycles like new. You can't go by appearances with people, but you can go by how the vehicle has been respected. Some will clean it for the first time, so be wary of that possibility as well.
Anything used, let the buyer beware. Good luck!
I would rather have good compression with good maintenance. Good compression is only as good as how much longer the motor will hold together. Next month you could be replacing it. Often an engine or trans replacement exceeds the used car price. Oil and filters are so cheap, even synthetic vs a new block.
I have my cars detailed. It may cost a couple hundred a year, but immaculate in and out recoups it. People can lose hundreds or more over condition. In the interim you have a nicer vehicle to drive as well. If you go cheap, you usually get cheap when you sell. Less dollars back.