New roof, new siding, new plumbing, new electrical system, new kitchen, 75% of windows are brand new and fully renovated house.

Are these ground-mount system or roof-mount? 

So, don't overreact to their maintenance requests.2) A landlord should eke out every bit of life from a roof, HWH, etc. and put band-aides on it until it makes economic sense to replace it.3) Maintain to the Neighborhood!

If you see very low appreciation in 4 years but rack up astronomical operational costs much of what you accomplished is working yourself in the ground for no apparent reason.  

Hi,My rental property's roof is 20+ years old. 

If the plan is for them to live in the house until they are no longer able (either they pass away or move to a nursing home), then it may be that you and your husband are paying for all of the repairs and things like replacing the roof...or maybe they will treat it as their own home and simply give you the money each month to cover all of the expenses.I'd be concerned if he has siblings to make it clear that the house is yours (though with the in-laws paying for everything the siblings may see it differently) and what happens if you divorce?

I had a property tented for termites, which broke some concrete roof tiles.  

Pretty much all major components were newly installed / fitted and done to a tasteful standard (new metal roof, plumbing, electrical, kitchen, flooring, bathroom, doors, new hvac, decks, vinyl siding etc) and I have visited and walked through 3 times and even been under crawl space to inspect a repair that was previously noted on an inspection to the foundation after termite treatment which looked to be a good job.

Also lot of insurance companies to give new quote asking for proof of new roof replacement otherwise not giving quote which concerns me as my roofs are very old replaced by previous owner or original roofs. 

Also in your area that is a little rural if its well and septic makes sure those are checked by professionalsif it has city sewer make sure you do a sewer scope on the line running to the street.. and of course make sure roof is good etc etc.and for sure you can offer what you want to pay.. they may not accept it but its up to you.also ask title company to give you current owner.. and if you want simply make a back up offer in cases the wholesaler cant close this happens a lot and you get a better deal.