Overall the more space the better. However I have limited space. It usually takes me 2 days to get everything organized where it does not look like I am a hoarder. Most of my stuff goes into bins seperated into categories. Stuff I sell on amazon goes into on tote (cds, dvds, and books that are in good shape and that would bring me at least $3, if it dont match those cats then they go into a different media tub to be sold in a garage sale.)
Next is the junk, broken, plain trash, products that have no value go straight to the side and I call my contact up to pick it all up for $50.
Then its the all wood furniture that needs repair, those go to the side till I have time to fix them.
Collectibles go onto a display shelf that I plan on CL or taking it to an auction house.
Then a space full of totes that I will be CL that does not fit in the other cats.
The biggest space is all the misc stuff that I will end up in a yard sale. But those are organized even more. Each Categorie has its own tote or box. Small hand tools. Power tools, small kitchen appliances, purses and wallets. Shoes, media that wont be sold on amazon, cords have their own place if I dont have anything that matches up to them (mostly cell phone chargers), computers IT stuff, household electronics, costume jewelry, pictures and frames that are not collectibles, then misc stuff I think of as crap but know will sale.
Then I have a small jewelry box that holds all my scrap gold, silver and platinum. (by the way has anyone came across platinum in a lkr?)
Last is the good jewelry like heirlooms, james avery, and other expensive jewelry that is worth more than scrap.
Sorry long list, lol, And I keep everything tightly packed in my garage.