We have a jetted tub in our home. Pretty useless, but we went with it for resale value. My cats spend time napping in it, so I guess it serves SOME purpose!
Pool maintenance can be done very cheaply, Google the BBB method. My last house we had a large pool, in Central TX heat, full sun for 12 hours/day. One case of bleach each week at Costco, ran about $8. I was diligent about keeping my water crystal clean. Most important thing I learned is that when you start using the "easy" chemicals, it adds all sorts of crap to your water, which then requires another product to take that out of the water. Brilliant marketing from all the pool stores!
We also had a hot tub at the last house. I started looking at Craig's List for gently used stuff, but came across a company that refurbs the older tubs. Got a great one, which they tested and refurbished, for about $3K. Since it was older, my utility costs were a bit more, but nothing too crazy. Hubby & I have chronic pain issues, so we use ours as a necessity, not a luxury. Still, when you add in the cost for the level placement $1,500) and the hard wired power ($2K), it was a bit more anti-mustachian than we anticipated. We left it behind since it was getting older, and we suspected some internal leaking and other maintenance issues that made it worthwhile to include with the sale of the house.
This new house is very different for us. We recently purchased a basic tub for $3K from Costco. Check your state laws, many states will allow you to waive the tax if your doctor writes a script that it's medically necessary. This one is plug n play. The jets are not nearly as powerful, but it's better insulated, and it works just fine for our needs. We had the builder pour a very large patio, so the pad was ready to go once Costco put this model on sale.
I check my water weekly, and use powdered Bromine to keep it sanitary. Filters can be reused for a long time if you soak them in some TSP and rinse well. If your Total Alkalinity is off, you can regulate that with baking soda or a touch of muriatic acid. So far, our TA has been perfect, so just a cup or so of powdered Bromine/week, which I usually buy in bulk at Spa Depot or Ebay.
Like anything else, you can optimize to provide efficiency. :)