When considering what flashlight to get, one of the things that should be considered first is the size. Yes, output (lumens) and run time are important, but the best output and run time flashlights available are useless if it is the wrong size.
Our categories separate the flashlights into what we see as their best fit. Some (such as the Logan Keychain) can fit in multiple categories, as such we chose the category that seemed most fitting. By limiting each flashlight to be in only one sizing category, we avoid situations where two or three categories are mostly filled with the same flashlights.
Here are the sizes we divided them into and a description of the intended use - as well as highlighting a few that are borderline fitting into another category.
Keychain - The intended use of keychain flashlights is to attach a few keys to them, so the flashlight will never be left behind. If included with car keys, it will always be on hand while taking the car. If included on house keys, it will be on hand when out of the house. Attach a storage locker key and always have it on hand when dealing with your locker.
Two flashlights stand out as borderline fitting better in another category.
Peak Logan Keychain - this one takes up a lot of pocket space so it is best kept with a minimal number of keys and not attached to keys where weight could be an issue (like car ignition keys).
Eagletac D25AAA - while keychain capable, it isn't actually the design focus for this model. The small size (runs on AAA) is what lends it to being suitable as a keychain flashlight.
Pocket - These flashlights can be small enough to use as a keychain flashlight, but they would be better suited to only minimal keys attached - becoming an anchor for locating the keys. Some may not even have an option for attaching to a keychain. These are paired up with the EDC because they are basically just an EDC that fits in a pocket.
There aren't any borderline ones to highlight since these are mixed with the 'size above' and the ones that are borderline below are in with the keychain group.
EDC (Every Day Carry) - These are mostly just a larger pocket flashlight - so they don't really fit in the pocket as easily. These would be best carried in a holster, in a pack, or clipped on a pack. Some have a pocket clip which can keep them in a pocket that they would otherwise fall out of, or allow them to hang from the outside of the pocket. These are also just great to have around the house should the need arise, or bring along on camping trips. Sometimes Personal will be used in place of EDC, Pocket or as an encompassing of both sizes.
A few highlights that are borderline fitting in the group are:
The LD41 (680) of which a newer version has been released with a newer LED, and it just doesn't make sense to keep them together in the same category.
The E50 (XM-L) which still works fine, but again it just isn't bright enough to fit in where it used to.
The GX25A3 which is reasonable as an EDC, any bigger and it would need to be bumped up a category.
Tactical - These flashlights are typically similar in size and shape. The most uniform part is that the body is typically 2.54 cm (1 inch) in diameter - so it can be used in a typical gun mount. This makes it popular with law enforcement, military, hunters and airsoft enthusiasts. Another common feature of tactical flashlights is the 'reverse grip' or tail cap button, which can be swapped out for a 'remote tail switch'. Flashlights of this size can also be used as EDC.
There aren't really any borderline flashlights, if the body is the correct diameter and it has a tail cap switch, then it is tactical. Some that could be borderline (M25C2 and M30LC2) are covered because we have Tactical and Professional in the same category. If we were to separate the categories, we would have to decide where to put them at that time.
Professional - This group is the hardest to specify, it is actually easier to specify what they aren't. These have some feature (such as size) that make them less suitable as EDC flashlights. They don't fit in the Tactical group because they don't meet the requirements or have a feature that interferes (such as a larger head). They aren't Search and Rescue because they don't throw far enough or aren't bright enough.
These are best suited to two styles of use. First is limited use where the flashlight is kept around for when it is needed and put back when done - such as around the home or at a work place with areas that are poorly illuminated. The second is in situations where the flashlight will be constantly used and not be put away or holstered for long periods of time - such as a work place with low lighting or when minimal lights will be on (such as night security).
There aren't borderlines in this category since these flashlights are all ones that didn't fit in another category. It is easier to decide if the flashlight meets the requirements for the other categories. Can it work as Search and Rescue? Is it a Tactical? Is it small enough to holster carry reasonably?
Search and Rescue - Often the largest flashlights and their priorities are in the beam. As newer models are released, previous models may get bumped down to Professional. While classed as Search and Rescue, there are plenty of other situations where they would be useful. There are four aspects to consider when assigning a flashlight to this group.
First is the most obvious, throw distance. Being able to scan over a large open area allows the opportunity to see something sooner
Second is also fairly obvious, output. The more light (lumens) it puts out then the more illumination there is.
Third is beam profile. This is a little more complicated to decide what is better since it is more situational. To properly explain the impact of beam profile may take a whole blog posting. Basically, a narrower angle means more throw while a wider angle means more area.
Fourth is run time. Obviously, all the throw and illumination doesn't matter if it only lasts a few minutes. At maximum output the run time is usually at least an hour. Run time is another aspect that would require a long explanation due to the dynamics involved.
There is one flashlight that is borderline being bumped up to this group, the GX25L2-R22. While we are out of stock at the time of posting this, if we get in one of the updated versions then it might meet the requirements (full details are not yet available for the updated version).
Headlamps - These are fairly straight forward. The flashlight is either designed to be a headlamp or it isn't - except the Wizard series, which can be removed from their head bands and be used as pocket flashlights.
Lanterns - With diffusion and LED arrays, these are more about covering an area (such as a campsite). These are great for lighting up a room in a power outage. At a campsite, one big advantage is that these lanterns can be taken inside a tent or other locations with limited ventilation - places where a propane lantern have high potential to be lethal.
Bike Lights - We currently only have Fenix bike lights available because they have a feature most bike lights don't have. Just like in a car's 'low beam', these bike lights are designed so the top of the beam is reflected down. This is for two reasons, first is to prevent blinding oncoming traffic and pedestrians while the second is to put more light on the path ahead. This makes them a more safe and effective bike light than most bike lights that I've seen on the road today (which are usually blinding me as a driver and possibly blinking as well - which strobe is known to disorient people and animals.)
Those are the sizes we sort the flashlights into. While this is the first thing to consider when selecting a flashlight, that doesn't make it the most important - unless of course all that matters for the intended use is the size of the flashlight. Sometimes it just feels good to use a hefty flashlight.