You betcha I print my pages! I print 99% of the pages I make in Shutterfly books. I did print a couple in Blurb format a handful of years ago because they were cheaper, but then Shutterfly started their unlimited free pages sale and I was back to them again.
I print all of my pages in 12x12 sized books and the older I get, the happier I am that I stuck with the larger size. Ha ha!
As for how often... I scrap until I fill or nearly fill the 111 page limit in a Shutterfly book and then I wait for a sale.