One thing which I have recently thought second-hand dealers should do is to provide a timegrapher measurement of watches for sale. It would really help to avoid getting sold a "dud", or a supposedly recently serviced watch which is actually dirty and running dry. I've been using mine for a few months now, and given that they only cost £100-odd, it seems like a small investment for what it allows you to achieve.
One thing which I have recently thought second-hand dealers should do is to provide a timegrapher measurement of watches for sale. It would really help to avoid getting sold a "dud", or a supposedly recently serviced watch which is actually dirty and running dry. I've been using mine for a few months now, and given that they only cost £100-odd, it seems like a small investment for what it allows you to achieve.