It is my understanding that Rachio is primarily a consumer product. If that is true, I believe a truly great UI would allow the user to use values commonplace in the consumer world.
IMHO Rachio does a great job with its UI in so many ways — which makes it all the more frustrating and unbelievable, that they still don’t directly support drip systems (and no, I don’t consider linking to a consumer’s spreadsheet direct support).
I would love to recommend Rachio to friends and neighbors, but I can’t because of the lack of true, direct support for drip. I live in a high desert, and at least in my neighborhood, the majority of people use drip systems almost exclusively.