You want to be in that zone where you are self sufficient enough that in pays for itself. Then you could think about quitting a job to be able to devote even more time and energy to grow hundreds of a few particular crops instead of the usual family size in the backyard. I'm blogging about my family's attempts at self sufficiency, growing and preserving food etc. Next year will be my first big garlic crop if we can keep things together financially I think I may have finally found my calling.