If the plants are getting to the point where they're needing to be watered constantly, it might be about time to move them into larger pots. Check them to see if they're rootbound, and if so, get them into bigger homes. They'll be happier with the added room for roots to dig, and you'll be happier with a soil that retains some level of moisture again.

Be careful about testing with your finger, as soil without an abundance of roots in the bottom can collect moisture down there. I prefer knowing how much the pots weigh when completely dry, then lifting them to see if they could use a watering.