at the risk of necro-ing this ancient thread, but just to give my 2ct anyways:
if you buy a second hand machine cleaning and oiling is definitely needed and usually a first step you should take. After regular use, you will need to do this as well. This doesn´t usually mean take the whole cover of etc, but for sure the bobbin area and bobbin holder. If you do not clean this regularly then you cannot expect good results, since even a tiny piece of lint can cause missed stitches.
Needles need to be replaced regularly, since they get dull after a few hours of active stitching. But of course they shouldn´t break from stitching by itself. To test if the machine is stitching and feeding well, let a piece of cloth (ideally 2 layers of simple woven cotton, no stretch or other material) straight-stitch through and let the machine feed the fabric by itself.
When actually sewing you should try to only guide the fabric left/right. the machine will handle the front/back direction by feeding.