What's worst case scenario?

[waste]

Welcome to the forum ! I'd say the worst case scenario is a tree comming down on your pool Seriously, the worst case is that you'll get an algae bloom and have to do a lot of cleaning and add a few cases of bleach (or more). I believe that most people here use the algicide as insurance against algae - if yoou have sufficient available chlorine in the water, the algae won't grow. If you're not going to use the algicide, add an extra bottle of bleach when you shock the pool prior to closing, just to be sure that you've killed all you can before slapping the cover on. (I assume you follow Ben's Best Guess chart for shocking)
IMO, you may have a little algae in the pool when you open in the spring, but it shouldn't be too bad - just in case, plan to open the pool a week early next spring to allow for any cleanup that may be required.

[Poconos]

I'm in Northeast PA and have never used an algecide. I keep the equipment going as long as possible, usually mid November before I blow the buried pipes, so I can circulate a little every few days and keep the chemistry right. I also open early and the only time I get an algae problem in the Spring is when I get lazy and cheap so I don't circulate as much and the water warms a little. I'll see it and get right on it.
Al