I try to keep every can from every plant I've ever planted. It's like a badge of honor for me.
I won't part with them unless I'm sure they are going to be recycled.
I will still keep a big stack around the house in case someone comes over and wants divisions.
They are super rad for lazy seed starting. As in "Hey, might as well just start it in a 1 gallon pot"...
I'm happy and proud to announce that this represents about 1/3rd of what I planted this weekend.
Disregard the mess beyond the giant stack of cans ( A la "These are not the droids you're looking for"...)