Termites are dangerous precisely because they work silently inside wood and walls for a long time before the damage becomes obvious. The first sign to watch for is a thin mud tube running along interior or exterior wall foundations — the sheltered tunnels termites use to travel without exposure to light.
Other signs include a hollow sound when you gently tap wood, discarded wings near windows and doors after a swarming season, and paint that bubbles or peels for no clear water-leak reason. If wooden floors start feeling soft or uneven underfoot, that's usually a later sign of moderate-to-severe infestation.
For prevention, minimize direct wood-to-soil contact, fix any water leaks or moisture buildup around foundations right away, and inspect exposed wood periodically, especially in damp parts of the house. Catching any of these signs early saves you from major structural repair costs down the line — don't wait for the damage to become visible before acting.