Buying second hand coilovers, what do I need to look for?

So I'm keeping costs down for now. I've not bought second hand coils before so I was just wondering if anyone could tell me what I need to check for when buying them? The guy is taking off his car the same day I'll be picking them up as he's selling the car. so they've not been sat for a while or anything like that.I'm saving for a house and once that's out the way I'll be buying a proper set of new coilovers. via /r/cars http://ift.tt/2sXK1IV