Ok, so we live in a fairly small apartment, and with two kids there isn't really any room for a dedicated hobby space. So I have to use the kitchen table for painting and modeling, and I need to be able to pack all my stuff away after every session.
In order to be able to do this, almost everything except the cutting mat I use to protect the table is packed in different kinds of boxes. The most essential are my "Painting" and "Building" boxes. They constitute the space I am allowing myself to allot to these activities. If I want to build something, there needs to be enough room in the "Building" box, and if I want to paint something, I need to have room for it in the "Painting" box. This forces me to finish stuff I've started, and so far it's been working pretty well. However, I've recently ordered a Stompa, and I'm not sure how I will fit it into these boxes...
I stow my paints and tools in a box under the table when I'm not painting. The size of this box also forces me to limit how many paints and other stuff I get to buy, however I'm allowing myself to keep spray paint cans in the cupboard, where I by the way also keep my modeling materials (plasticard, pipes, cork, sand and other stuff) and all books and models that are still on their sprues.
Then there is one final box, and this is an important one - the bitz box. I try to keep it organized, however I do have a big bag within the box (the pink one) that I haven't had time to sort yet. The deal I've made with myself is that I don't get to buy any new bitz before I've sorted the ones I already have. However I have a hunch that this is a promise it will be difficult to keep.
Anyway, despite not having a lot of space, and definitely no dedicated space, I've found a few tricks that still allows me to manage the hobby in a reasonably organized way.