Rookie question about renting attachments

I don't rent much equipment so, sorry if this sounds like a rookie question, but I thought I would ask it anyway: When renting various attachments which use hydraulics, like an auger, for example, what potential issues (if any), am I opening my machine up to in terms of different fluids, additives types and any crap which may be in the lines from previous renters' machines? Is this really an issue, and if so, do you have any tips or advice? My machine is an 1845C.

Thanks,

Rookie question about renting attachments