I took a gap year. I most likely wasted it in a way, but I did do some travelling and stayed a long while in a place (In Greece) that I still go back to. That taught me about living frugally (£3 a day budget) and being self reliant ... bought a return plane ticket for £60 and sold the return portion when I got there to someone who had "over stayed" and needed to get home. In those days, you could go to the airport and check in, then give them the boarding pass. I actually hitch hiked home. For much of the year I played music (in a band called Or Was He Pushed?) in Huddersfield. Bill Nelson put me on to them when he played the Kirk .... I asked him if he knew any decent musicians in Huddersfield, where I knew I was moving to with my folks. That sort of got a lot out of my system and, waddya know, I ended up involved with music for a long time after Uni. I also started working on doors (got roped into it through doing martial arts) ... something that kept me alive financially through my Uni years and beyond. That said, there was a lot of women and booze and all that frippery, which meant my father told me I'd wasted my gap year. He may have been right, because when I went to Uni in Birmingham, I ended up doing a course that bored me witless anyway ... even if it did pave the way into film and telly.
My son went directly to Uni from School 2 years ago. He dropped out at the end of the first year as he hated the course (physics). He had a year dicking about/sleeping all day/gaming all night and has just started again in Sheffield doing something he loves.
I realise, this contribution to the hive mind consensus does not offer any definitive conclusions, but I hope you enjoyed reading a load of waffle.