A pool can be managed with weekly visits if the pool has a salt water chlorine generator or chlorine injection system. Pools need a daily dose of chlorine to stay sanitized.
With no SWG, pool guys rely on stabilized tablets (which dissolve slowly) to maintain that daily dose. The problem is these tablets leave behind chlorine stabilizer. When chlorine stabilizer (CYA) levels get too high, the pool is no longer manageable from a chemistry perspective. The pool guy will tell you you've got "chlorine lock" and it's time to drain the pool and start over. What he really means is the CYA level is too high.
So what do you get for $120 a month. A guy that stops by, pretends to brush the pool, drops tabs in your floater, drops a bit of acid, cleans out the skimmer basket and takes off. Filter cleanings are usually not included, so figure another $75+ for that when it's needed.
Invest the first month's pool guy payment in a test kit and DIY. Nobody will care for your pool like you.