The most reliable watering advice is also the simplest: check the soil before you water, not the calendar. Push a finger an inch or two into the compost. If it feels moist, come back in a few days. If it feels dry all the way down, it is time to water. This one habit eliminates most overwatering and underwatering problems at once.
When you do water, water thoroughly. Pour slowly and evenly across the surface of the soil until water runs freely from the drainage holes, then let the pot drain completely before returning it to its saucer. This ensures the whole root zone is moistened and flushes out any salt build-up from tap water.
Drainage matters as much as frequency. A pot without holes or a pot sitting in a puddle of water creates anaerobic conditions that rot roots even in soil that appeared to dry out on the surface. Terracotta pots are particularly forgiving because they wick moisture from the sides; glazed ceramic and plastic hold moisture longer. Match the pot material to the plant's preferences.
Many popular houseplants come from humid tropical environments and appreciate more moisture in the air than a centrally heated home provides. The most effective methods are grouping plants together, placing pots on trays of damp pebbles, or running a small humidifier nearby. Misting delivers a brief boost but evaporates quickly and can encourage fungal spots on hairy-leaved plants.
Seasonality changes everything. In winter, lower light and cooler temperatures slow plant growth, which means roots absorb water more slowly and soil stays wet for longer. Reduce watering frequency from autumn onward and pick it up again in spring when you notice active new growth resuming. Your finger-test habit will tell you exactly when to shift.