Ordinary incandescent lamps (non-halogen) have a service life of 2 years. Despite the fact that after two years the lamps still retain their performance, a dark coating appears on the walls of the glass bulb, which reduces the luminous flux of the lamp.
Before replacing the incandescent lamp, it must be switched off.
Caution: Do not handle the glass flask with bare fingers. The traces left by the fingers evaporate and the evaporation products are deposited on the reflector, darkening it. Replace the lamp only with a lamp of the same design. Accidental stains on the lamp bulb are removed with a clean cloth without the use of alcohol.