BBC and shave every day. Including everything it's probably about 5 minutes. That's quality time for me which I look forward to rather than dread. Haven't missed a day since I went sly nine months ago.
I am not BBC but at this stage of the game and I look back on what I had before and it would be BBC ! I let mine go a day or two and then use my HB Sport with HB Slick in the shower. Just depends on how much hair you have and how much stubble you want on the dome .
I'm part-time BBC. I have a full head of hair but love the feeling of a sly head, so when the mood strikes me, I go sly for awhile - sometimes keep it for a month, sometimes for a year or so. Until I get bored and want to change my look by growing my hair back and try a few different styles.
But to answer your question, with my thick course hair, maintenance of a smooth head is tough. In terms of the way it feels, there's a HUGE difference between shaved and one day's growth. And by day 2, the stubble is visible enough to look quite different than the shiny clean shaven dome. So when I'm bald, I shave daily. And even though I'm pretty good at it and can do a great head shave pretty quickly, the maintenance effort is always a factor in deciding to grow my hair back for awhile. But I always know that at some point, I'll miss the look and feel of a smooth and shiny bald head and will shave it all again.
My regular barber is no longer the least bit surprised when, on a hot summer day, I "call an audible" in the chair and tell him to lather it up and shave me bald.