If you think you want to mix and match, then I'm another vote for doing it. No one else will notice or care. I did 2013 rounded and 2014 squared. But I missed a few 2013 pages, and when I went back to do them this year I accidentally scrapped them in my squared off 2014 style. I debated redoing them because I thought it would bother me, but it turns out I'm just glad to have them done and barely notice the mistake when I flip through the album. (If I'd done it deliberately and mixed and matched throughout, I'm sure I wouldn't notice at all. I just do since I know it was a mistake and there are only a couple pages like that in the whole album.)