That's cool but watch out for hoarding. While I agree with picking up discarded fixable or like new appliances, there are so many of them out there that one may end up hoarding.
We collected up suitcases off the curb that in theory need minor mending (no smells, certain problems left behind), and over time the backlog has built up. Time is also an ingredient, here; in the best case it takes fifteen minutes to prep a curb suitcase, in the worst (cleaning stains, etc.) the suitcase might need to sit around in a ventilated area for days over the course of treatment.
As for the Hall field sensor yeah I know I probably could have found an equivalent on Digikey and saved $15 or so when you factor in the shipping, but the convenience factor and knowing that I just fixed an otherwise fine $1700 commercial shredder for $25 is fine.