there are so many things to look out for when buying used it is impossible to list them all but I will give you my top five. 1 look for one that is being used , look at the sellers other equipment if you can, try to get a picture of how he treats his tools.2 look for one with parts readily available, look over the tractor and see if it has any issues that are currently being lived with and price the repairs.3 make sure if you are getting ready to buy one that you test it thoroughly run it in all gears warm and cold check for leaks , and loose bolts.4 I look at lights pretty closely as they will give you an insight into the life of a tractor , ie if the original lights are hanging by the wire and have clearly been broken for a long time you know the previous operator is a let it be kinda guy and doesnt jump on repairs.5 fresh paint in my humble opinion fresh spray paint on a used tractor is a big warning sign, not allways bad but it opens questions up that you should ask , allways bring someone with you when you look at a prospect , so that you have an unbiased opinion and so that you have a whitness to the claims the seller makes , ask lots of questions, like does everything work as it should? does the tractor operate well through all gears and temp ranges, you really cant ask enough questions.knowing tbn the guys will say you need to tell us what your doing howbig your lot is whats your price range and a hundred other variables I think the things I have listed will help regardless of those things. good luck