Feel below the surface
Touch the potting mix a little below the top layer. A dry surface alone does not tell you whether the root zone needs water.
Water thoroughly, then drain
If the plant needs watering, moisten the mix evenly and allow excess to leave the pot. Empty standing water from outer containers.
Check the conditions
A plant in bright light and warm air may use water faster than the same species in a cooler, dimmer room. Pot size and soil texture matter too.
Lift the pot
Learning the difference between the weight of a wet and dry pot gives you another practical signal, especially for small containers.