Brian,
I bought a hand held metal detector from Ebay…it is on par with the HF. It works ok, then I had the opportunity to get a better one when our local courthouse replaced theirs. The one from the courthouse worked much better on 2-3 inch stock but really did not improve the results on 1" and smaller stock. If you have a planer that is a little bigger, those blades are huge money, and I have gone to checking EVERYTHING I plane. I nicked the blades on a piece of walnut from a lumber yard. Blades for my Jet are 150.00 a set…..I believe that you should do it on all wood you use. If I remember right, the ebay wand was 35.00…..
Mike

Mike