Bo will probably cut his hair when he gets to his mid-30's. That's usually about the time it happens for long-hairs. All the dudes from Metallica cut theirs off around that time. My husband cut his when we was about 35.
The thing is with these guys...they get so used to the way it looks that they're scared to make such a drastic change. Of course, there are a lot of women like that too. Still wearing the mullets, or feathered looks.
I really hate to see a middle-aged man with long hair. Those guys from Skynard were pretty scary looking. Bleah. Now James Hetfield and Lars Ulrich (Metallica) look SO much better with the short hair. And I was one of those women who always liked guys with long hair. It's something you need to outgrow, I guess.