Ain't it the pits! There is no one-size-fits-all rule.
To whom it may concern,
Those beautifully recessed armpits have masculinity written all over them. Though I generally prefer these sunken treasures appearing with hair, in fact anything can, if taken to excess, turn out being a bad thing. Having armpits that can be confused for a fully grown chia pet or even your pet cat, needs a little work on them. I guess you might refer to this as "pitscaping" where the traces of hairs end in a thinning out trail at either end of the of the armpit. Something resembling two stacked rectangular boxes simply won't cut the mustard anymore these days.
At the opposite extreme, even those guys that feel they must be totally hair free everywhere else, need to remember to keep the armpits off limits or possibly needing some symmetrical pitscaping where both pits look like mirror images of each other and are tapered at the top and bottom. People with two rectangular boxes per pit can, especially if they have black hair, appear to be self-sticking Velcro and once you bring your arms down, you won't be able to raise them again, due to the Velcro appearing patches of underarm hair. Certainly for paid performers like dancers appearing for an audience with children, shaving may be the way to go. No one wants to see a male ballet dancer with furry underarms. The same applies to swimmers. Other sports require underarm hair to pass the screening device to get to the male locker rooms.
Long after a guy has gone completely bald, they can be counted on to have a full crop growing inches away from their bald head. I wonder how many bald guys would willingly trade their underarm hair for hair on their head.
Sincerely,
Stimpy, Pit expert extraordinaire PEE