Yes, I think the "droop test" is highly effective. You have to develop an eye for it, because you want to catch it when it's just beginning. They'll let you know when they're thirsty.

Droop test is good. If your mix drains well, over watering won't be an issue. I also use kabob sticks or smores sticks as probes, you can get them at the dollar store.

After you observe droop test and do finger test then you would figure it out how often/when to water.

Temperatures and container size make difference too. In PNW I used to do it every 3rd day. But it was cool up there and I got less than 5 hours of direct sun.

But here in deep south I water my containers almost daily, unless it rains.

WIth good well drained potting mix , watering often does not cause a problem. But then every 3rd watering need to fertilize with about 1/3 recommended strength. As the water drains so does some of the nutrients, especially nitrogen.

I'm in S. Cal. so our weather from now thru July is fairly temperate. Our really hot months are Aug. thru Sept. As others have suggested I think the finger & droop tests will work for me.

Since I will go on a vacation or two during the growing season, I use a drip system on a timer. Right now, with our temps at 50-60F and plants 12-18" with a few blossoms, I give them 15 minutes every other day, with 1 GPH emitters. That will be changed as the weather warms up and plants get bigger.