Wouldn't it be easier to compensate for these costs via salary increases? Not everyone will have the same needs, and attempting to track everyone's expenses seems more complicated than necessary.

Although, come to think of it, it might make sense to mark some amount of money as an "equipment stipend" or similar on paychecks. That way, it's clear to both parties what the funds are intended for, even if there's no actual mandate on how to spend them.