Serious question.
If you came across say an FW3A for $20 , would you buy two? Or more?
If you believed you found the best EDC, would you buy two or more?
If a light you love, is offered in multiple colors and multiple emitters, would you buy multiple units?
I will answer first: Absolutely, positively YES. I have multiple S2+’s, D4’s, D4S’s, etc. If I love a light , I will buy more than one.
Hell Yes, I’ve got multiples of about 5ish lights. Sometimes it’s the cheapest way to buy them, I bought 3 Olights warrior X pro’s for 300 where as to but them single on sale they are $140. This is AUD not USD, everything is damn more expensive. Got 4 little Sofirn SP31-p’s… great little 2000lm gift lights with decent UI, decent combo-beam, both 18650/18350 tubes. Sometimes you buy a light and then want a different tint. Despite the flashlight market moving so fast with new designs constantly hitting the shelves, a good light is a good light and can be relevant and useful well into the future. I wish new emitters would develop faster.
If you came across say an FW3A for $20 , would you buy two? Or more? FW3A? Unlikely.
If you believed you found the best EDC, would you buy two or more? Yes, i will buy one identical light as spare, nothing more than that.
If a light you love, is offered in multiple colors and multiple emitters, would you buy multiple units? Yes, but in a sensible manner of course. 
I wouldn’t buy multiples just to have the identical light in a different color. I would for different emitters. My rationale typically has lights filling specific niches or tasks.
I have but usually when a deal comes along I can’t pass up. A few years ago S2+s were on the sale threads here for like $7. Even with CW temp. I could not resist.
No, i don’t buy bargains for the sake of a bargain, has to be something i want.
Yup! And have done. Generally one for me, one spare, maybe another spare, and maybe some for gifting if appropriate.
Only if i actually want the emitter and colour but generally no, i have amassed more lights that is justifiable outside of this forum but i’m not a collector that way.
I’m no collector, in fact I hate having too much “stuff” laying around and at some point it feels like becoming a burden to me just slowing me down.
Don’t get me wrong, I like to try a lot of different lights just to find out what works for me and what I like or don’t care about, but at some point I’ll probably just sell what I don’t use and be happy with the ones I like best.
Long story short: nope, no doubles for me! In case my favorite may die on me I’d rather buy something comparable equipped with the latest innovations.
Sometimes I do.
Nitecore Tube for example. Bought 15 when price was sick low. Gave away as gifts.
Mike
yes, I have more than one now:
AAA Thrunite Ti3 (3 total)
AAA Maratac (3 total)
AAA Tool (3 total)
Novatac (2 total)
Utorch S1 Mini (3 total)
Jetbeam Rotary (7 total)
Sunwayman Rotary (4 total)
(and have resold multiples)
.
lights I bought multiples and resold, keeping only one for myself (and do not intend to buy more):
Sofirn C01
Nitecore EX11.2
Tool AA
Thrunite T10T
Olight i3e
.
Lights I only have one of, and would buy another if I could:
Nitecore D10
Olight i3s
.
Lights I bought, but would not buy again:
HDS Rotary
Eagletac D25A
Mecarmy PT16
===
my lights with High CRI LEDs:
Ten 219b 4500k 9080 sw45k
one 219b 3000k 9080,
one 219b 3500k 9080,
one 219c 4000k,
one LH351d 5000k,
one LH351d 3500k
one XP-G 3200k
one E21a 2000k
one 5600k yuji
two XP-E2 Red (660nm and 730nm)
.
Low CRI, pending modding:
four XM-L2 Cool White
two XP-G Cool White
Yes, I sure do. 
Yes, absolutely. Multiple color bodies and those with different LED's. Keep for my collection (addiction) and to give away as gifts.
i never thought i would, but now i find almost half of my collection has at least 2 version of one model light. different emitter options is what gets me buying more than one of a model. Seldom its the finish / color (like copper or titanium). right now i have more than one:
(3) Emisar d4
(3) Noctigon kr4
(3) Noctigon K1
(2) FT03 mini
(2) FT03
(2) MF01 mini
(3) Convoy M21c
(2) Convoy M21a
(2) FireFlies e07x Pro
Not usually, but I made an exception for my Maratac AAA twisties since I didn’t want to have to move just one light between my work pants, casual pants, and pajamas every day. Plus I had to have a copper one, and then a brass one….
oh
there would have to be a reason like cheapness
or maybe new FW release, anduril 2 maybe
i would not just pay full list price for a backup i do not currently need
Only a very few...ones that I really like and use (and want to keep using well into the future). To me, if it's a winner, I don't need to find the others at a discount or used, I just want to be sure I have them (and I don't usually get lights that are above the $60ish range anyway, so it's no big deal). After learning to swap parts and mod a little bit, it makes all of this easier, although having spares of emitters and drivers and rings and springs and such...cheaper and takes up little space, anyway. :)
For me, currently, it's only C8F, S2 variations, spare original Nicron N7 (those are neat...or were), and of course the venerable MiniMag AA which are never used anymore and rarely looked at (but they're like family). I wish I had gotten a second FW3A from the first batch but I've hesitated in buying another from later iterations of it. Many lights have been fun or interesting or useful but there's no way and no reason to get duplicates of those. I don't really buy or sell, either, so hoarding some models or collectibles doesn't interest me.
My grandfather slipped a tidbit of wisdom my way when I was a teenager but it didn't hit home until many years later:
"If you find something you really like, buy two, because it may not be there when you want another."
That has been so true for me more often than not.
I’m now currently at (gave some away) 18 D4V2, each different from all the others in a meaningful way. 11 titanium, 2 brass and 5 aluminum.
Each offers something the rest don’t, each one fantastic in its own way.
I also have 9 KR4, 6 titanium and 3 aluminum. Here I have some actual duplication with 4 titanium 2000k mules. They are such beautiful tail-standing mood-setters, multiple are sometimes needed for maximum effect.
There is bit more, but I’ll stop my text-wall here so nobody dies.
Depends a bit on what you consider to be multiple:
5*C8( +): XM-L2, Green Flat, 400nm UV, 365nm UV, SST-40
4*S2( +): XM-L2, White Flat, 400nm UV, 365nm UV
To me they are all special in their own unique way.
Too many times. :person_facepalming:
I want or “need” multiples of lights I like and use regularly, just to not be without one in case one breaks, gets lost, stolen, etc.
Too many lights that I tend to not use, whether because of the tint, the UI, some other quirk. You buy ’em to try ’em, and there’s that one shortcoming that knocks it out of everyday use.
Also, too many lights that are “too nice to get rid of”, but I find myself not using ’em. Eg, of C8s, GTminis, P30s, lights in the same general form-factor and function, do I really “need” all of them, or should I just settle on one and ditch the rest?
Then there are the improvements, eg, the original TO46R, then the same ’46R but with Nichias. So what do you do with the lower-CRI original? Or the whatever-model Nitecore that you get in the typische CW, but later score in a much nicer NW?
Frankly, I want to thin out the herd… bigtime… but I gotta confess I’m loathe to take a huge bath doing so, especially since most of them are not just shelf-queens but box-queens, ie, brandy-new in the box except for testing/trying. Most “used” lights go for, what?, half price? Not much distinction between well-carried and BNIB. That hurts y’know? 
Same here. Crappy 1B emitters in generic gray/black ano, but they make hella nice and cheap hosts to throw together something in a pinch. In fact, the complete lights were cheaper’n empty hosts.
I don’t usually buy multiples, but if I find a basic light that’d be good to give away or use as a host, I can’t resist buying a few.