How to vet maintenance and repair costs for out of state investor

[Rich Sund]

Just like the title asks - is there a way to vet maintenance and repair costs that my property manager is charing me as an out of state investor? I realize this might be part of the "cost of doing business" out of state, but I'm curious if there is a way to confirm these costs and how to do it diplomatically. I was referred to my property manager by a trusted friend, but I can't help but feel like I'm being over charged for bogus fees. 

Also, is it reasonable to ask for receipts/invoices for every repair made (ie - fixing front door, snake drain, etc) or should I only expect invoices for larger ticket items (ie - replacing water heater, lead testing, etc). Thanks.