I don't have a watering schedule, I play chicken with my girls. As close to wilting as possible. In fact, I have a pic that comes in handy. This is from last night, my Critical Kush and is dry about 3 inches down, and possibly farther. Barley any sign of moisture. You can see the leaves just starting to wilt slightly.
I would rather see my plants wilt slightly from underwatering than from over. And PeeJay is right as always, they recover amazingly fast if you miss it slightly.
I comment on the term schedule only because things change with these girls fast, into flower, suddenly nearly full of roots and the water intake can increase suddenly. Try to look at them with the schedule in the back of your mind but look at your girls with open eyes not allowing what you "know" to prevent you from seeing what they are telling you.
That is as zen as I get. Be right back
Bob