Actually, fun fact, body hair can grow very fast!

For example, there are many stories of young men in the US getting in trouble for having stubble by the end of the school day, despite being clean shaven when they arrived in the morning.

And I follow a streaming group that does D&D, where the DM has previously mentioned his facial hair grows in so fast, that he needs to shave several times through the day if he's wearing a costume portraying a female character for costumed events.

Some people do have genetics that make it so they seemingly can't grow facial hair at all, though I wouldn't say Harvey counts under that, since he has the mustache already.
So he'd probably shave and trim up the beard once a day to keep if how he likes it, which is what most men tend to do, except when they're actively trying to grow the beard out.

It doesn't matter in the context of the comic obviously, you just have fun telling your story like you want to, but learning something new about the real world can also be fun, so I just thought I'd share my knowledge. :)

thanks you very much i wasn't aware of that problem ! i learn something new , thanks to you ! thanks a bunch ! °W°