My last career venture pre-covid had me meeting with a lot of pool owners and pool builders for structural repairs. (All gunite.) I built my own pool with subs in 2018-19 using the advice I am going to share from meeting with lots of pros and homeowners.
1. Make sure your pool builder uses #4 vs #3 rebar... It's a cheap date for much more integrity. Trust me.. You do not want a cracked shell.
2. Make sure there is a hydrostatic relief plug in the bottom of the pool. Never drain the pool below the returns (jets) without using the relief plug. Water under the gunite pool will absolutely float that sucker. I have seen it many times.
3. Stay away from salt. We started using them in 2008-10 in Texas and its much harder on the equipment, natural stone coping or decking, and especially the plaster. Re-plastering a pool was $5-6K on average and you tend to get 10-12 years with chlorine and 6-8 with salt. Everyone I met that had a 5-6 year or older saltwater pool was having issues.
4. In the same spirit, stay away from the automatic chlorine tablet feeder on the pump. I have been told the high concentration of the chlorine at the pump severely cuts down on the lifespan of seals. Just buy a $20 floating chlorinator. It's easy peasy.
5.Make sure they put 50% or more quartz in the plaster. It extends the life big time.
6. Variable speed pump is the only way to go.
7. Absolutely get the polaris pool cleaner and booster pump. Your best friend.
8. Absolutely get a safety cover that blocks out 99% or more of UV light. First, its great peace of mind for the 5 months you won't use the pool. Second, it will keep all of the leaves out and make your life wonderful compared to the poor saps that have to scoop leaves all winter. Finally, it will really extend the life of your plaster by preventing algae. Also, it will massively reduce chemical usage in the winter. I would just shock mine once every 6 weeks through a skimmer to keep it perfect all winter and spring opening was a breeze. As an added bonus, it keeps water temps warmer in a cold spell. This winter when the deep freeze hit Texas, the water temp never got below 40 degrees in my covered pool and everyone else iced over and had water freeze in pipes. (I bought my cover online from leisure living, 24 X 40 custom made for $1650. Took me and a buddy 2 hours to install the anchors and about 1 hour in the fall in spring to install/remove by myself. Absolutely worth it.)
9. We went with a sports floor pool instead of diving. Number one reason is diving is fun for about 30-45 minutes and gets exhausting. Everyone ends up hanging out in the shallow end and there is little room to play games. Ours was 3.5' on both ends and made it to 5.5' in the middle. Great for volleyball and you can still have a slide for the middle if you want. Also, lots of home insurers won't cover diving. Most people I met with a deep end regret not having more shallow space. The other option if you have the space and $ would be L or T shaped with a big shallow are and a deep area for diving.
10. The Spa is overrated and a future source of potential problems. The number one structural issue I saw was the spa settling away from the rest of the pool. Typically the pool is dug 5-10 feet into the ground on stable soil. The spa usually is elevated above the pool a few feet and is not very deep, so that area is only 1.5-2.5' deep into the native soil. But, it probably weighs 12-20,000 lbs when full of water and if you have clay that shrinks or sandy loam the is subject to erosion, either way you are looking at a cracked shell and plaster if you get any movement... Plus their are massive amounts of plumbing leaks that happen under spas. Since you are on a slope, if you do build a spa, you absolutely want it on the uphill side.
11. The pool heater. I didn't get one. It's expensive to install and operate. The reality is we swam in Texas until Mid October in an unheated pool. By that time you are kind of done for the year anyway. Wore out. Plus with the leaves falling, I was ready to put the cover on. The value would come in the Spring. You could probably get it going 4-6 weeks earlier. The coolest thing I have seen is an HVAC heat exchanger that heats the pool with the return line from your AC. It actually save you money on the electricity by making your AC run more efficiently. In Texas we usually started running the AC during the day in March some days and by April you were running it everyday. The guy I met with the heat exchanger said it would heat his pool about 5-7 degrees in a week. He was swimming in 80 degree water when everyone else is at 72 or 73... I promise, that is a huge difference and probably extended his pool season by 2 months. Again at zero energy cost and a slight savings on the AC bill. I highly recommend exploring. Before I moved, it was going to be my next purchase... About 1/3rd the price of a getting a natural gas pool heater installed.
https://www.hotspotenergy.com/titanium-pool-heat-exchangers/
I could go on for days and have already, but these are some of the things that jump out. For the record I think the gunite/plaster pool is the only way to go. They just look so much higher end when done right. Completely customizable too. Good luck. Shoot me a message if you would like to discuss further. I have tons of pictures of my pool build and my buddy's that I helped on.