I have 9 canister lights in my kitchen that I've replaced with "replacement LEDs." The lights are on a 2-way switch, one of which is a dimmer. Things were good for about 2 years, but now all 9 LEDs (well, 8 out of 9) are fairly dim -- still usable, but very different light output than when they were new. Perhaps 50% light output.

I'm wondering if this is a result of the dimmer switch. The dimmer is about 12 years old, so was constructed in the pre-LED era. I find it more likely that I have trouble with a single component (the dimmer) than that most of the canisters are failing.

Do I need a special dimmer to switch LED lights?