When I plant flowers in flower pots and hanging containers, I put a piece of florist foam over the hole in the bottom of the pot. It still allows for drainage when the rain soaks the soil, but when I forget to water the pot, it keeps the water from running out of the hole without moistening the dirt.
I don't buy new florist foam. I save foam from cut flower arrangements. It's easy to cut with a sharp knife.
My watering routine is that when I go out on the back porch to drink a glass of lemonade, I dump the ice on a plant when I am done. The ice melts slowly, which gives it time to soak into the dirt. It means that the plant will get a little water every few days, which is better than no water at all.