After every occupancy, the property must be cleaned and fresh linen provided. Be sure you understand where this cost goes. If you do, that means they are laundered in your property using your appliances and your electricity. Also there will be an expense as linens and towels wear out or vanish. Another cost issue involves maintenance.
Many agents have no maintenance capabilities in-house.
Scrutinize a number of actual monthly statements. If they want to provide copies with the owners name and address blacked out, that's reasonable, but do see some actual statements. Some agents limit how many weeks you can occupy your property. Don't buy that for a minute. Travel agents are a very small part of the majority of rentals, which occur in the already busy summer months.