I used to be a hardcore, 8.5" by 5.5" planner user and wouldn't consider any other size. I couldn't fathom why anyone would go any smaller, LOL!
However, there are good reasons why one might change to a smaller size.
1. Change in circumstance.
I've spent the last 12 years of my life homeschooling my sons which included weekly co-op type meetings where the moms were responsible for teaching classes, planning events and a number of other activities. I took my half-size planner everywhere, and with homeschooling and homemaking and keeping up with health things (kidney transplant), I had plenty of information to keep up with.
A year ago our co-op part of homeschooling stopped, and so did a lot of activities. It's one of the reasons I went to a personal-size planner. I no longer needed all that space to keep up with my new normal.
2. Save paper (if you print your own inserts)
I've printed my own inserts from day one (except for that one time I tried to stay faithful to Franklin Covey dated inserts). It has to do with my creative side - I love creating them and trying new things! I have my printing process down to a science! My inserts are compact size: 4.25 x 6.75 and I get 3 pages from one letter-size sheet. I pre-cut them and load up my printer.
3. Those things can get heavy!
Well, they can! Mine was packed full, and because I don't like carrying my purse much, I put in my debit cards and also stuffed it with whatever else I could get in there. When I decided to try a personal size, I test-drove an inexpensive planner to see if I liked it. At first, I thought there was no way, but I quickly learned to enjoy how light it felt. I also liked the challenge of making new insert sizes and including the things I needed to make them the most productive.
4. Make more productive choices
When you have a smaller planner, you have to be choosy about what you put inside. Things that I would normally stick in the pocket of my half-size planner don't necessarily make the cut in my smaller planner. I have to ask myself, "Do I really need to keep this?" and "Is there a better place to store this?"
What size planner do you use?
Would you ever consider going smaller?