I have 6. Then I bought 6 C01Ss. They’re great emergency lights, and I don’t regret it since the C01 is no longer available.
Occasionally, a new emitter I want to try will become available in a model of light I already own (S2+, S21A), and I’ll get another just to try the new LED. But, generally interesting things come along every once in a while that kinda take the shine off the old stuff. Right now, I like my B35AM and GTFC40 so much, I’m really glad I didn’t buy any more puke-green SST-20 lights than I did just because they were all the rage at the time.
I pretty much have multiples of most of my AAA or “Keychain” lights because they were on sale/special/ bogo/ free with shipping charge, available in multi colors, or just plain cheap (Thrunite Ti3 V2, Sofirn C01, C01S, OLIGHT i3EOS, I1R EOS, Lumintop IYP07, Wurkkos WK01/02), and a few of those are discontinued. The only 18650 light I doubled up on was Sofirn SC31PRO 5000k with Anduril 1 (primarily because I wanted one in 18350 config, and An-1 is the shizz). I have two Sofirn IF22A, one black, one silver. Great lights. All the rest are lone rangers (so far).
Most of my lights are AAA, or 18350. I have a few AA/14500 and 16340. I own Zero 10440 or 18650 lights.
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By LED:
The vast majority of my lights have Nichia 219b LEDs, plus a few other High CRI LEDs. I own Zero lights with Low CRI LEDs (unless they are hosts I like, for an LED swap).