There are generally two types of lighting mode for the flashlights, from high to low or from low to high. I found many people have disputes on the lighting mode. Should the flashlight enter the high lighting mode or the low lighting mode when turn it on? When you are in emergency or need high brightness, it's more convenient to enter high lighting mode directly once you switch on. While, if you are in camping and getting up in the night, turn on the flashlight, low lighting or even moonlight mode will make your eyes more comfortable. Some flashlights provide memory mode to enter into the last lighting mode, but some doesn't have memory function with simpler design. It seems difficult to choose. So high-mid-low or low-mid-high, what do you think of it?
Depends on the type of light in question. If it's a big light and especially if it's a larger thrower. Chances are you will only really be using it on high not low. So this type of light should default to HIGH.
However if it is a tube style 18650 or smaller EDC light. You will most likely want a way to go directly to low/moonlight. As this type of light is far more suited to close quarters and indoor use. These should default to Moonlight.
UI's can be sophisticated enough to cater for both scenarios however. The BLF A6 driver isn't a bad stab at it or some of the newer variants. If you have an electronic switch or dual switches then it is even easier to offer instant access to either end of the spectrum.
However it is worth considering. If you are using moonlight, you probably aren't in a hurry. Where as wanting High/Turbo is likely to be a more rapid demand.
Using a mechanical clicky you can have short and long presses so to allow moving up and down through the modes. This is how the BLF A6 driver works.
For an EDC light I think
1 click = moon
2 quick clicks = Turbo
This would allow you to essentially turn it on in either mode. And you won't blind yourself getting to moonlight.
From Moon light a long click should increase brightness
From Turbo a short click should decrease brightness
This way you would not need a mode memory, because each end of the spectrum would be quick and easy to access. And you can travel in both directions, allowing you to increase or decrease brightness at your discretion. It would also be intuitive and easy to use.
If you wanted the blinky modes (strobe/SOS) you could either have them as hidden modes or programmable on/off. I prefer the latter.
I would think on most light you need 4 or 5 outputs
Moonlight -> Low -> Med -> High
or
Moonlight -> Low -> Med -> High -> Turbo
If worried about too much heat, Turbo could auto step down to High are 'x' period of time.