Say you buy a watch from someone you don't know (as it usually happens), you don't trust the person or you just don't care what they say.
How do you decide if a movement has been serviced or is simply in good condition ?
Apart from the fact that said movement is clean what other signs or tests do you have to find out whether a movement is in good condition and has been serviced (more or less) recently without taking it ALL apart at first glance ?
Please share. :)