Depends on the color, quality, and hair cut. I've done short pixie with white hair, then put sky blue lowlights in. It worked well because I both have blue eyes and a blue undertone to my skin, unlike a lot of people who have yellow, orange or pink as their undertone. Made me look a bit like a marble statue which I thought looked cool.
I've also done cherry red hair, which I can get away with but I'd never try neon anything. It rarely looks good outside of a rave, and fades fast, even with professional treatment.
A really good way to do fun colors without looking crazy is to mix it with something neutral. I do something called chokecherry red, where my hair is a slight chocolate brown base, red undertones and has an almost purple hue to it in sunlight. So if I'm in artificial lighting, it looks much more adult, a dark red brown, and in the sun it's a very fun purple that shimmers to red and almost looks like it has a black base. Keep in mind I choose to add more violet in it when getting it professionally done. Mine costed around 70$ plus tip, but my hair is extremely strange and does what it wants, meaning it'll hold red dye longer than just about anything else, so I can get away with not dying it for like 3 months (I have very honey blonde roots and the red makes it look perposefully done despite being much lighter.)
I would never do greens, oranges, or harsh yellows again, they look terrible on me, only darker, cooler colors work except for red. I might do a pink for fun after dying my hair a blue tinted silver again, but just do lowlights in my bangs for it.
Oh, and here are some examples I pulled off bing. Inside would look like this:
Outside would typically look more like this:
Edit: I tried to look for examples of when I go silver, but it was difficult to find exactly what it was, since it was so personalized.
Cut was like this:
(Yeah yeah I know, lesbian cut. It surprisingly works on me)
Base color was more like this: except the roots were the same as the tips, not all dark. And the lowlights had this color:
I also had to do a very shitty edit because the lowlights were waaay too dark, but the base color was basically this:
I did eventually add the lowlights to be more neon blue, and on me, the color faded to a more snowy white instead of staying silver (my hair apparently doesn't like blue) neon blue did not look good on me but I still liked it for a fun experiment.
Tl

r: you can do it tastefully but who the fuck cares? It's your hair, it'll grow back. Idc if it's a bit juvinile for my 30's, I like it and most people I care about think it suits me.