That is a smart idea to learn what you use this season and save up for another barrel for next year. I like that your barrels are black so they should stay warmer and able to function for more of the year. That would be my concern where I live. Perhaps you could install a solar powered chicken bucket water heater so that it never freezes and you are able to keep water all year. But you don’t really have a lot of things to water during the winter and it would just fill up once and not be used. So using it just during the spring-fall sounds like the best strategy.