Everyday

I don't know anyone who has full-time to devote to organizing. However, we can all do a little every day, and let it become a habit. Doing just a few things a day can lead to big changes over time, and you have to be patient.
Organizing is as personal as you are, and what works for you might not work for someone else. You have to approach it as an experiment. Not everything you try will work the first time, and that's okay. Looking on it as a process, rather than a project, will help you accept that as you organize, your needs evolve. There's no right way and no one style of organization.
I'm a kinaesthetic person, so I go by where things are in space. As you might imagine, organizing and putting things in different spaces was an enormous upset and I would literally have to take pictures as I went along to help me find things until they reached their permanent home (and I still can't find things from time to time without a search until I assimilate the new order).
So be prepared for a lot of chaos and change. Don't worry, it's all worth it!