The best way to tell whether a houseplant needs water is to check the potting mix and know how dry that species prefers to get. Drooping alone is not enough because overwatering and root damage can look similar.
Check below the surface
The top layer can be dry while the center of the pot is still wet. Check deeper with a finger, wooden skewer, or simple moisture gauge appropriate to the pot size before deciding.
Know how dry the species prefers to get
Succulents often tolerate more drying than ferns or tropical plants that prefer more even moisture. Use species and season as context instead of applying one rule to every pot.
Pot weight is a useful clue
With experience, a freshly watered pot feels noticeably heavier than one approaching watering time. Comparing weight helps prevent watering solely because the surface looks dry.
When you water, water thoroughly and let it drain
When the plant type allows, water until excess drains from the holes and empty the saucer. Frequent tiny sips can leave shallow roots and dry pockets within the root ball.
Sources
- University of Minnesota Extension — Watering Houseplants — Watering, drainage, and water-stress signs in houseplants.