Let them know how much you value them as a client... maybe offer a free ceiling fan or paint a wall or free landscaping one time visit.. if they renew.

As far as saving on heating costs, if you haven’t already, tune up your heating system it will operate up to 10% more efficiently, and you might be able save more heat by weatherizing the building better: caulk any gaps causing drafts, insulate any uninsulated cavities where you may be losing heat especially between cold spaces like attics and under floors or in walls where the insulation has sunk down or never existed (you can find these poorly insulated areas with a thermal leak detector gun which are only like $30-50 these days), use weather stripping around doors and windows, use storm windows or the cheap plastic window insulating stuff, open any drapes to let the sun heat the home during the day, close closet doors, etc. and turn the heat down to 50-55 (I would get there early or use a smart-thermostat you can control from your smartphone to warm it up before showings though, as a cold house might turn off a renter).

Are these visible issues, behind walls, etc?

With more expensive/lower cap rate properties you can get greater capital appreciation for each incremental dollar of NOI.For lower cost/higher cap rate properties you will need to focus more on acquiring and retaining high quality tenants and you will likely need to spend more in ongoing repairs.I think that if you really dig into the details (I.e. underwrite) a decent number of different classes of properties you will get a bit of clarity on what strategy is best for you.All the best,Ronan

I have rejected 2 applicants who screened well on paper but when we did the in-home visit found hoarder levels of junk, bugs, animal feces, holes in walls, unreported pit bulls, etc. 

The other is a pool area fence that has a steep hill that works normally as a natural wall.  

We have made decent progress:Replaced a foundation wall/shored up the main floorPut a 416 sq ft addition on the existing 2nd floorRemoved all stucco exteriorNew sidingReplaced windowsReplaced doorsRemoved rotted front porch and replaced with covered front porchNew steel roofKnocked down a tree in the back yard that caught a power line and ripped the neighbor's mast off their house on a Sunday morning.Replaced the stairs to the 2nd story adding an L so you don't bump your head at the top of the stairsFramed 2 BR and a full bath in the 2nd story additionRight now we are sitting at $20k for the house, with another $37k in repairs and carrying costs.

Expect a super high bid on trim if it's a different color than wall/body.  

To go off my topic for a moment, I worked in wall st asset mgmt, I thought I'd read that with the entry of private equity/asset mgrs to real assets, real estate returns have pretty much converged on stock market returns?

Or you can be a real mean and report him to the state licensing commission for Negligence, violating the agreement and misrepresentation or whatever other BS you can come up with to nail him to the wall.