I used to collect leaves but I got tired of the broken bottles, rocks, and dead cats. I had a full size cargo van which would fit 80 bags.
Fortunately our acre now sports a few trees which supply a lot of leaves. But I especially prize the spruce & pine needles which don't have to be shredded. A nice thick layer is no impediment for asparagus, garlic etc. from last year but keeps new weeds from getting a hold. It is easily moved aside to plant new stuff.
I have 6 big mulch piles which I dig out and rebuild, one a year. They work rather slow because I'm not too fussy about what goes in them. Twigs, some dirt, and no turning.
