I have several PDF files that I print regularly (together). Some are printed as double-sided, and some are printed as single-sided. When you combine PDFs into one document, there's not an option to keep some printing as double, and some as single. When you hit print and choose the option to print "Double sided," it prints double-sided for all. Wish there was a way to have them combined in one document, but have separate printing properties. May work-around is to add a "blank page" after the single page PDF, but that gets messy. THanks