I have a Hawkeye Spa, which is a local company in Richmond. We have had it for 10 years. DH is handy and Hawkeye is great. I have called them 2-3X over the years and asked about replacing something. They have emailed me technical specs of what to do (diagram of how to) and the place where to buy the parts with the part number. Also, one time, the H guy said, as long as you are replacing the X, while you have the part pulled out, you should replace Y, as your spa is 7 years old and the part is only $15, but you'd have to pull out X to get to it. We did as he advised. I guess others would call a repairman, but I am glad that Hawkeye is willing to do this for us.
For the 1st 2-3 years, I used it average of 2X every 2 weeks, some weeks more often. At 10 years out, I average about 15-20X/year. I esp. love it in the snow--makes me feels like I'm in Colo at a ski place. Lack of use is really a time/activity issue. If I were retired, I'd likely use it a lot more.
We have a redwood casing and the corner of it just started rotting, as it is in the area of our house that gets the bad winter winds/snow (our windows on that part of the house also had wood rot and had to be replaced). So, I recommend getting poly/trek/etc. surround and not real wood. Almost maintenance free. Sort shocked it's still works as well as the day we got it 10 years ago. We have replaced the calibrator/control panel on the top, that $15 part, and nozzles, which just pop/screw off, and now rebuilt with compound the corners of the outside surround.
also, make sure to cover with extra plastic, etc. when it snows, as the covers will absorb moisture, become heavy with wetness and then mold and you have to get a new cover. Putting the extra plastic cover prior to snow helps a lot. We replace our cover every 5 years or so, costs about $350 mail order.
lastly--test drive whatever you are considering, esp. the strength and placement of the jets. I have a bad neck, so I wanted powerful jets positioned to hit neck/upper back. I have a corner seat with lots of mini back jets and 3 neck jets. It's fantastic.