Had the same problem with a 20 year old microwave/venthood with a cracked frame. Replacement with a new mw/vh from a bump & dent (couldn't see any damage after install) was $100 and well worth it to have a new model in the kitchen. And yes, I charged the tenant -- they were rough with the mic door and that caused the frame to crack. I don't depreciate appliances when a tenant overtly breaks them. I charge replacement value. May not hold up in court, but I haven't had anyone take it to court yet.