Sorry; I rarely do containers. When I do, I ‘let the plant tell me’: if it’s not droopy, it doesn’t get water; if it starts drooping in the afternoons, that is a temporary condition, unless it is still that way the next morning. I’m always more afraid of over watering than of under watering. The exception is the Topsy-Turvy tomato planters: they, per instructions, get about a half gallon a day, unless they’ve gotten a good dose of roof runoff.
For the garden, I usually go with the top inch or so being dry or barely damp, then give them a good shot of water to give them their inch/week.
For large water guzzlers, like squash family, and cabbage family, I plant almost rim-deep a large coffee can or similar size deep container with drain holes around the base of it between 2 of them, and keep filling it until it stays pretty much full, in addition to their regular watering. I can also put fertilizer in it to get it down to the deeper roots.
Your info. about watering is good and tells me more about when to water. Thanks.