Buying used gear entails some risk. The seller had reasons to part with it, and those reasons may be clearly stated - or they may not.
Caveat emptor, indeed!
I picked up an Olympus E∙M10 for under $150 when most bodies are still over $200. A dealer had it, so the original owner was not available to describe any issues (and is not compelled to reveal all, in any case). It's in great shape for the most part, fully functional and takes great images. Yes the SD card slot has lost its spring, so the card stays in without tweezers; that's part of the risk and is an inconvenience but not a real issue for the price I paid.
I may have found the larger issue though.
After trying the WiFi feature several different ways, I looked online and found that, for many E∙M10 owners, WiFi starts to run and immediately stops again without connecting. The fix is a hardware thing, and costs about $150 - in this case, it would double the cost of my bargain.
Ouch!
- but how important is WiFi for this camera, to me? I have a GX7 that works just fine with WiFi, so for the second body this really isn't a major issue. It doesn't mess with my shooting in a typical setup - in fact I've not used WiFi yet on a m43 body. Some day a camera will be attached to a telescope and take photos, and it would come in handy. On the other hand a 2-second timer would suffice.
I need to try out more features to see if my bargain is still truly that. The Live Time and Live Composite features are in fact the reasons my 2nd body is Olympus, and short tests look fine. Video looks decent as well, with functioning stabilization too.
I had speculated that the E∙M10 could actually replace the GX7 at one point, but that's not a good idea with the WiFi problem.. we'll see if other problems appear.