This question was in the Philofaxy Facebook Group. And I could answer in a second. And I should write too much to explain for what and why.
Let's start with the why!
I have ADD and I want everything perfect. I can't say no for things. So I need all the stuff and all the stuff don't fit to one (two, three) planners. It's ok, until I can manage the all the planners. I was once on a Filofax meeting In Zurich, with suitcase. Others asked if I have a planner for my Filofaxes? :D No, it's in my head. and now, let's see what everything I use?
Main planner
An A5 Malden purple. This is the base of everything. I made a separate monthly booklet for it, to spare ring space, but not only that's why was this a great idea, I don't have flip back when I do my weekly review, I take out and see. I keep here notes, tasks (they will be move out), ideas (on a flyleaf just on post it notes), personal and family projects, main part: planning: 5 year pull out for holidays (in personal size, but never mind :D), weekly planning (no weekly calendar), daily pages, some wo2p for journaling, and miscancellaus section, in ABC order. Really very mixed stuff like online orders, contacts, infos, etc.
Work planner
A5 Malden ochre. Notes, yearly and monthly planning, projects, infos about my business, like color schemes, etc.
Social media planner
Carpe Diem in pink color. This was first a section in the work planner, but it's got too stuffed, so I took out. This is not really a planner, because I do the social media planning in Asana. I keep here some ideas, printouts like "how to write a good newsletter", on piece of paper, what posts I have already written (I try to make it once a month).
Daily greatness business planner
I don't use this how it could be, because it contains weekly calendar, and I plan in my dailies. But I never learned about business, and this planner asks the most important question for a yearly and quarterly planning, So I use that part.
The 17 dividers system
This is my version of the 43 folders system. In A5 Original Deep Aqua.
Informations
A5 Finsbury Black.
Notes
A5 hot pink Domino. Notes I took like on parent meetings and I want to keep, notes I took when I read a book...
Wallet
Pocket Pennybridge, with one year monthly calendar only with appointments, notepaper, and wallet stuff.
Always by my hand handy cuteness
I was so lucky to get a pocket Malden in the red color (hmm, what is the name...), and as you can see, I have mostly A5 - what could I use this for? Hmm, mostly note taking! It's so small, that I bring with me when I go to bed, to the couch, etc. I was so often not brought my A5 with me, and not written down little thoughts while I knitted or read. When a tasks pops in my mind, I have a post it on the first divider, I write it there, and in my daily routine I have a task: check this out! :) So far I love the idea.
Meal planner and recipe binder
Personal purple Domino. I don't really use this for planning any more, but it keeps my recipes and freezer inventory.
(Youtube)
So, let's count... 10. What a nice round number :) I hope I didn't missed any...