I said, "doesn't sound like an emergency, I'll get you guys a screwdriver set, but there's different screw heads that I'll have to show you if you never done it before".On the other extreme, I got a middle age tenant who used to be a home improvement contractor, belonged to the sheet metal workers union working for a municipality, was furloughed at one point.

Hi Ting,I've had Pest Control companies that layed down a DMZ of sorts outside the buildings.Fire ants, ants, and a lot of other crawlies seem to stay away from the DMZ area--keeping them out of the house.I've had them do it in the pouring rain and on nice days.Maybe they do something like that in your area.If it's a problem, you can scheduled ongoing service for it--where they will come out and re-apply.Or you could pass the info on to the renter--it's less costly then her hiring an attorney (unless she is govt subsidized and gets free attorneys via legal aid).They also do a building inspection inside and out--looking for entry points that need to be "Repaired", but ants get in through the smallest cracks.If you have a slab foundation, they may be under the slab and coming through a crack in it--exterminators can handle that.One or two phone calls will get you a quick price, and being there when it happens to take notes on where the tech says to repair to prevent other insects coming in might be a smart move.I've seen long lines of ants outdoors coming up a metal handrail to an apartment and going into a tiny space at the corner of a window and into the apartment. 

On a side note to this, I try to always use glue joints on under-sink traps unless I've got metal threaded pipe under there.

See if outsiders compressor coils are dirty.

What is it constructed from   I assume its something like (2) layers GWB on metal channel on joists or trusses at 16" on center w/ 3/4" floor sheathing and 1" gypcrete and insulation. 

Roof pitch 12/12-New shingles and edge metal $9k (plus replacing plywood where needed)-exterior painting $6k (definitely will be replacing some cedar boards here, but not clear on how many, maybe 10-15) -rebuild four stair walk up on porch $1.5k-carpet tear out and LVT (4.5mm clic, 12mil wear layer) throughout $15k-replace 40ft of cedar fence $5kLet’s assume that there are few to no surprises and the work quoted is the only work necessary.Let me know if I’m missing any info that would help.

You can also have issues with an AC coil freezing if you don't have proper air flow.

This makes me feel a bit better, but I had better get shop drawings from the metal guy doing the stringer to ensure all these are dialed in.

All recommended flashings/metal caps were installed/present and sealants reassed and looking good.

It ALWAYS needed the coils cleaned (I had a Golden Retriever and she loved the sound of the exhaust to sleep by) I learned to get every spec of dust and dog hair away myself but still it didn't last too long.