Razorwear

If like me you're a guy who wears tights, and you probably aren't, you may have experienced the following. You pull on your legwear in the morning and sometimes find, presumably when it's colder, that your leg hairs stick out through the gaps in the weave.

Also, if you're a bloke who used to use one of those foil shavers, you will be aware of the system of two sharp meshes cutting hair by sliding against each other.

These two ideas can be combined. Figure-hugging garments which consist of two adjacent layers of fabric which slide against each other and have fibres sharp enough to cut hair parallel to the skin - obviously not perpendicular, which would just lacerate you. So you stand naked in the cold, your hairs stick up, then you pull on your figure-hugging underwear or balaclava. Then you rub them a few times and they proceed to snip off all your hair, which can be on your scalp, face, body, limbs, wherever. You have then managed to dress and shave in one easy move, and your hair never gets longer than the distance between your skin and the surface of your underwear. The hairs are cut off on the outside of the clothes and can be easily brushed off.

I would suggest that on the whole this would be more popular with women than men, at least on the body, but it also applies to the head. There are two acceptable haircuts: none at all and completely shaven off. The latter is easily achieved with a skullcap of this nature. Face stubble can also be easily removed by doing the same with a balaclava, which could be temporary.