My house came with one in 2004.
A fairly large, 8'x8' octagon. Held 6 people easy. 1HP pool pump and 4500 watt pool heater.
Didn't take much to get it operating initially but then...
Only using it one or two nights a week made it difficult to keep the pH level consistent.
Seems like I was always overcompensating or not compensating enough.
It also took 3-4 hours to get to 100*. Leaving it on was not an option because...
After the first month, my electric bill was sky high.
The second month I adjusted the timer to only run for an hour and a half before I got home.
That meant I "only" had to run it about two hours more if I felt like using it.
After that my electric bill was "only" double what it had been.
I replaced the motor, the pump, and the heating element once. No big deal.
However, the fiberglass started to get 3-4 inch bubbles.
Drain the tub, dig out the bubble, repair, let cure, fill again with 500+ gallons- now the water bill triples or worse for that month.
This is before I got married and my wife moved in.
Before that she had expressed a LOT of interest in a pool.
I told her if she would agree to do half the maintenance on the hot tub, we could get a pool.
That didn't last one year.
She has only mentioned a pool twice since then, and all I had to do was say- "remember how much fun maintaining the hot tub was?"
The motor let go again a couple of years ago, and there were a couple new bubbles forming.
I decided not to fix it, and converted the electric circuit into a back feed for the generator and a place to plug in a 240v compressor.
This past year I decided to reclaim the space on the screen porch.
Using a 5" cut-off wheel in an angle grinder but mostly a sawz-all, it came out in 5 much easier to manage pieces.
The piping was actually harder to deal with than the main body.
The tub was inset about 2.5 feet and there was a flagstone border on a single course of cinder blocks supporting the lip.
Most of that went into the pit as fill.
I've put 3 wheelbarrows of dirt in on top of that but still have several to go.
I've also cup-wheeled the unfinished areas of concrete.
The walls will need stuccoed where the tub was because the crew that built it did some areas but not others.
That's where I am right now. It's kind of a slow, back breaking, *** busting process.
...but I better get on it as 95% humidity season is right around the corner.
Whew. I'm getting tired just thinking about it.