I've recently decided, now that I no longer frequently switch between platforms (Palm to Franklin Covey, Franklin Covey to Circa, Circa to Moleskine), that the best part of using a Filofax is being able to make necessary and helpful changes within the same platform. For example, I started 2008 using a 2-days-per-page diary. (In 2007, I had used a ruled week-per-2-pages and wanted more room and freedom.)
Well, I found that the extra room didn't do much more than let my handwriting get bigger, and crowd out the pages behind my rear tabs (left). Today I switched back to week-per-2-pages (unruled), and feel good about the decision (right). It only took me about an hour to rewrite 3 months of appointments. I'm going to rewrite the to-dos from the dated pages onto...well, To Do pages, so that I can move the page ahead from week to week.
I'm going to use my To Do pages differently, and I'll have to redo my tabs, but that's for another post.
I now remember the feeling of week-per-2-page constriction, now that I don't have the extra Notes space, and the weekend days are especially compressed. I now believe that the 2-days-per-page is ideal for someone who has almost nothing in any tabs except the diary (not me), or for someone who has a 7-days-a-week schedule with lots of clients, appointments, or events to track (at this time in my life, anyway, not me either).
It's actually very easy to change formats in the middle of a year with a Filo. Just take out all the unused pages in your current diary, and add the new format from there on. No copying necessary. I've done it that way before. In this case, I decided to use the switch as an opportunity for cleanup, so I rewrote.