You don't need Polyquat for your normal pool maintenance. Diligent daily testing and correcting your water will work brilliantly.

But, saying that, it DOES help if you let your FC drop due to sunshine, you take a trip and rely on someone else, etc. I like to add about an ounce and a half every week. That way, a 32 oz bottle goes for the whole summer. Since I watch for it to go on sale, and never pay more than $12 to $15/quart, I see it as cheap insurance. At closing, another quart and that's it for the season--$24-$30 more.

Do be aware that after you add PolyQuat, you FC level will drop and you'll need to add chlorine a day or two after. It's especially pronounced when you add a whole quart at closing. At that time, I wait 48 hours (during which time the FC drops), then push my FC up to shock level (15ppm in my case) and close it.

PolyQuat is insurance, no more, no less. You don't need it, but it doesn't hurt and CAN help.