Flashlights are of great use when there is only limited supply of power. Nobody is going to use the flashlights when there is enough power supply. So, one has to choose the flashlight such that it produce light as per the necessity. For example, when there is a power cut at home during any natural calamities, you need a powerful light that lasts longer, when you are in search of something in a cupboard or in a darker area, you need a sharper one. So, purchase it according to the purpose.
Handheld: This is best to use it at home or in places where you need to search for something in the dark. It comes with different type of batteries like AA, AAA and of different size.
Emergency lights: These types are best used at home and in offices which can be used during power failures. As this comes with a rechargeable facility, one can use it long and can recharge it multiple times when the charge of the flashlight goes off.
LED headlights: these are best used at workplaces. For example, men doing mining work wear it on their head to get a better view of the place. Similarly, these are best for construction works, hiking and to walk inside a cave.
Tactical lights: These are used by the military people and for government us. These are generally very bright LED used with firearms. Sometimes it is used to make the enemy blind temporarily. These are dangerous. So, need to be used with caution.
Diving flashlight: These are used underwater and produces a very powerful beam of light which helps deep sea divers get a clear view underwater.
The above are only a few of the flashlights in use, yet there are many which are used for different purposes.