I am definitely a newbie! But we went in with our eyes wide open. Hard work is not the only aspect of cleaning lockers. The unit we bought was about 45 minutes away. We rented the locker for the rest of the month (cost of $10) and went a few days later to do the clean out. We loaded everything from the unit into the trailer and brought it home.
So...this is where I am. My house looks like a hoarders house. (and unfortunately a lot of our boxes were in a wet basement before being put into storage. The locker itself didn't smell but some of the boxes are horrible). So one more thing to be aware of. This unit was full of empty boxes (good thing recycling cardboard is free..but a pain to break down, not to mention I can't even re-use any of them for eBay). I am looking at everything with new eyes. Most things I would donate or just throw out, I need to try to re-sell (ok junk is junk and needs to be pitched, but my profit is going to come from vintage canning supplies and jars I normally wouldn't even look at). I can't throw anything out until I go through all the boxes (one piece of something in one box, another piece of it may be in another).
All in all, we are going to profit on it...but not by just going in, buying and reselling. Now comes the sorting, clean up, listing on eBay, possibly saving for a garage sale (can't have one now, its winter here). Taking crap to the dump (this lady even saved the styrofoam that meat comes on!).