My own criteria is pretty generalized here, but, generally speaking, it either has to have:
1. At least double the OTF lumens (i.e. if my current brightest flashlight is 500 lumens, my next one has to be at least 1000). Incidentally, I look at pretty much everything the same way. A computer has to be twice as fast. A hard drive has to have twice the capacity etc., before I'll go with a new one. Guess I tend to think exponentially. There are of course exceptions to the rule though.
2. If it doesn't have twice the light output, it has to have a very nifty feature(s) and/or design advantage that would make me buy it. For instance, maybe it has the same output as my (current) flashlight but is half the size. Perhaps its size/weight/strength will help it double as a car jack handle
Then again, there's the rare instance where I might just buy a light cuz I like it for whatever reason
1. At least double the OTF lumens (i.e. if my current brightest flashlight is 500 lumens, my next one has to be at least 1000). Incidentally, I look at pretty much everything the same way. A computer has to be twice as fast. A hard drive has to have twice the capacity etc., before I'll go with a new one. Guess I tend to think exponentially. There are of course exceptions to the rule though.
2. If it doesn't have twice the light output, it has to have a very nifty feature(s) and/or design advantage that would make me buy it. For instance, maybe it has the same output as my (current) flashlight but is half the size. Perhaps its size/weight/strength will help it double as a car jack handle
Then again, there's the rare instance where I might just buy a light cuz I like it for whatever reason