Yes, much like the vast majority of halogen lights, H11 bulbs will gradually lose their brightness with continued usage. During operation, light bulbs are exposed to a steady cycle of heating and cooling, which causes the filament to progressively wear out, resulting in a decrease in the brightness of the bulb. It is suggested to replace H11 bulbs every few years or if they exhibit symptoms of severe dimming. This is because H11 bulbs have a filament that burns out over time.