That maintenance has to happen one way or another, hiring someone to do it can add quite a multiplier to the price. For example, I was recently looking at water heaters and called 4 different plumbers to get a quote. All of them came in around $5,000 for the job. The water heater they quoted costs $1,000 retail at Lowes. If you know what you are doing it isn't even difficult to install.

That said a layperson probably won't know the new code requirements in their jurisdiction and if you sell your house you'll have the inspector tut-tutting the work for one reason or another.

Hah, although, admittedly, when my AC died here I was looking at quotes for $17K for replacement (although I did also do the furnace at the same time, since both were early 1980s and basic models even then). "Why? I could buy the AC for $4K".

"Surely it wouldn't be too hard to undo/redo piping etc." But yeah, different refrigerant, different code requirements for vents and exhausts and drains. 4 people working for 16 hours, I saw where the money went.

> If you know what you are doing it isn't even difficult to install.

How much time does it take to acquire & refresh the skills and code knowledge, and how many water heaters can you amortize that over during your life?