When I was a kid, I just had a mop of hair on my head that I did nothing with except maybe comb it to untangle after a shower. I looked exactly like Bastian from The NeverEnding Story (1984). You could hold up a photo of me as a kid and that actor, Barret Oliver, and you couldn't tell which was which. Every time I went to the barber, my mother just requested they trim it a bit. Or she would do it herself at home.
Sometime in 8th grade, I requested a buzz cut, just to change things up. I requested a #2 on the sides and a #4 on top, while keeping the bangs a bit longer than the rest. It was cool to get your tips frosted when I was a kid, but I was never brave enough to do it. But I kept my bangs long in that style anyway.
When I was in the military, I usually requested a #1 on the back and sides, #2 or #4 on top, leave the front bangs area just a smidge longer than the rest, and taper the neck.
Note: In the US military, your hair can't touch your ears at all. So most military people will also have the hair trimmed away from their ears. I was fortunate in that no hair grows within a half-inch of my ears, so as long as I kept it buzzed, I didn't need to request a trim around the ears.
As long as I knew my wife, she always requested I grow my hair out. But I kept telling her I was in the military and couldn't have long hair. About 6 years into our marriage, she showed me a picture of Chris Evans in his Captain America role and said, "See? He's in the military and his hair isn't buzzed short. Grow it like this!"
Unfortunately, my hairline was already starting to recede a bit by that point and my bangs were super thin, so I couldn't grow my hair exactly like his. But I grew out the top, parted it on my right side, and sort of combed it up and back to blend my thinning hairline into the rest of my hair. Then I put a bunch of product in my hair to hold it in place.
Your hair isn't allowed to be messy in the military, and I have a problem with cowlicks when my hair is short. My hair grows straight out of my head, so it's always poofy. If it's cut short, it's not gonna sit flat against my head. So I needed lots of product to basically glue it in place while it was combed and parted.
So my new barber request was #1 on the back and sides (all the way up to the side part on the right), taper the neck, and just a light trim on top. Then put a bunch of styling cream in it to hold. I found a brand called "Mitch construction paste" (and later, I switched to a new one called "Blind Barber") that held firmly, but didn't turn my hair all crispy and hard. I could still run my fingers through my hair, and if it started to get messy, I could just wet and re-style it.
Then I retired from the military 4 years ago and decided I needed to get away from a military-style haircut. It was my last chance to enjoy longer hair before I potentially went bald.
I had a helluva hard time growing out my hair; every time it'd get shaggy, my military discipline would kick in and I'd run to the barber to clean it up, which just cut me back into a military-style haircut again.
Eventually, I decided the only fix was to shave it all off and start fresh. It took me about 6 months to re-grow my hair from completely bald, but it's finally grown out and no longer looking like I'm in the military. I basically went back to the "Bastian" hairstyle, but I kept it parted on the right side and comb the bangs back and over.
Nowadays, I just ask the barber to trim my hair and taper the back. Super simple. I comb and style it myself, so I don't need anything fancy at the barber. I don't use product anymore, because I don't need to keep my hair in immaculate condition. If it's a bit messy, it just looks more like a civilian hairstyle.
But without product, my hair is extra poofy. I almost have an Einstein look going on. My dad's hair was like that at the end of his life, so I wouldn't be surprised if my hair also continues to get crazier as I age.