We have a company open and close the pool, and a different company that services our auto-cover once a season when we open.
We do the weekly maintenance ourselves, but you can hire that out. Water testing weekly & adjusting chemicals as needed, plus vacuuming, cleaning out the skimmer baskets, etc.
I test the water at least once or twice a week (more often toward the start of the season, when things are still settling). DH runs our pool robot on the weekends and cleans out the filter as needed. I worked for a pool maintenance company when I was a teenager, so I have a good handle on the chemical side and it's easy for me to stay on top of things.