Because their roots can reach deep into the surrounding soil, plants growing in the open ground may survive some amount of drought. But container plants have only the soil in their pots to draw from. They depend on you for the moisture they need. Obviously they will require more watering than plants in the ground so here are a few tips to help.
Potted plant's need different things. Some need soil that is kept constantly moist, but not soggy and other shoudl feel barely damp. Many fare best is soil is allowed to dry out somewhat between one watering and the next. In these cases, don't water till the soil in the top half of the pot feels dry.
Even other plants need less water and you can let the soil dry out almost to the bottom of the pot between watering though not so much that the soil begins to pull away from the pottery sides.
Lighter soil mixes dry out faster than heavier ones and if you find the soil mix is difficult to wet, apply one of the wetting agents available at nurseries and garden centers.
After awhile you will develop a watering plan that suits your container collection. The important thing is to stay flexible and check the plant containers periodically and water the plants according to their day to day needs not by a set schedule. During hot or dry and windy weather growing plants may need watering several times a day. But in cool, still overcast conditions, you may get by with much less watering.
Don't neglect pots placed under eaves or overhangs in rainy weather. If no rainfall reaches them they can suffer from drought even during a season of daily downpours.