If you’ve ever found yourself dashing through a rainstorm to stop your in-ground irrigation system from running needlessly, consider a smart sprinkler timer. It can save you that hassle — and a ton of wasted water — while keeping your greenery and gardens thriving. (Note that these devices are variously referred to as smart sprinkler timers as well as irrigation controllers and any combination of those.)A smart timer also puts all of the standard features of a regular irrigation system on a smartphone app, and it automatically optimizes the frequency of waterings and the volume of water used based on your local weather conditions.The Rachio 3 Smart Sprinkler Controller (8 Zone) is the best of the models we’ve tested. It offers an impressive variety of useful features, and its app is a cinch to use. (The four-zone model we previously recommended is discontinued; Rachio continues to sell eight- and 16-zone models.)