the way i check,
i wiggle my finger down in to the soil and let it sit ther for about 30 sec if you feel that the soil is moist there good if it feels dry it may need water step 2
lift the container does it feel heavy or light. if its light and the soil felt dry water the plants etc.etc.etc after awhile you wont even notice your self doing this it becomes second nature to growers.
peace