After over 30 years in the construction trades and over 6000 physical inspections I have come across a few pieces of wisdom. One of the biggest has to do with maintenance. From my experience maintenance is the single most important aspect of any building or site. Most original construction is fairly good. Most products such as plumbing fixtures and mechanical items such as Heating and AC units will last a reasonable amount of time if properly maintained. That is the rub, if properly maintained. Unfortunately from my experience this is almost never the case.
When I read thorough manufacturers' recommendations regarding maintenance I never, and I mean never, see anyone do all the different things the manufacturer recommends. I usually get a chuckle at what is expected. (Realize that if these recommendations are not done the manufacturer is usually not liable if the product fails.)
Examples are things like roofing. The manufacturer recommends yearly inspections and maintenance. Nobody does a roof inspection every year.
Same goes for Heating and AC units, these should get yearly maintenance and in fact every 3 months is recommended with the filters being changed every month if necessary. Nobody does that. The ducting should be cleaned every year, nobody does that.
For electrical the panels should have yearly examinations for the connections to ensure they are tight and in some cases have the system examined with thermal imaging to see if there are any "hot" spots which indicates potential trouble. Nobody does that.
As far as plumbing goes the water heaters should be drained every year and the pressure regulator should be checked on a regular basis to ensure the pressure is not getting too high. Nobody does that.
The structure of the building should be checked every year to see if there are any issues such as settlement or any unusual movement. Nobody does that.
The site should be examined to ensure the exterior does not have any areas of moisture intrusion due to cracking in the sealing around windows and doors or any cracks in paint that need to be touched up. Ensuring no sprinklers are spraying against the building or trees that are pushing up against the planters or building. Looking at the parking lot to see if the asphalt is worn and in need of resealing before it needs 10X that amount of expense to have it resurfaced. Nobody does all of those.
Now having said nobody does the above mentioned items I know somebody out there is saying but I do!! Yea maybe but I bet you don't and if you do I bet you don’t do all of them along with the other couple hundred things to look and see if they are all operating properly or in need of some upkeep.
I also bet nobody goes and checks every toilet to see it they are properly secured to the floor or runs every faucet to see if they get hot water and if so is it in the proper amount of time and not too hot. Or that the flow of water at each fixture is not too much or too little. I know you get the point.