First of all, you should have a written contract or service agreement that outlines in detail what services are to be performed for an agreed upon price. Then use that as the measurement to first see if you are getting what you are paying for. Oh yeah, your pool should also be clean.
Rates can vary from pool company to pool company and service levels can also vary. It is always a good practice to get at least 3 different bids for pool maintenance so you can get a feel for pricing. Next, do a little research on the pool companies to make sure they are properly licensed and bonded.
You also want to make sure your pool service provider is not cheating the system by not having a contractor’s license, not paying employment taxes, not paying workman’s compensation or liability insurance, or other unfair business practices. You want to make sure the playing field is level.
Lastly, ask each pool company you are researching who they would recommend if they were not chosen. Call those companies and get a feel for comparative rates, keeping in mind that you can only get ballpark rates since each pool really needs to be looked at.