I am terrible at estimating the weight of the pots by lifting them, so in order to know how long I can wait before watering, I weigh the pot with dry soil before I transplant. Then you can weigh it again after you transplant, water and let the plant droop a little. Be sure to write down how long it takes, and the weight of the pot. Then you can weigh the pot to see how long until you need to water again.