I have IR filters on all my lenses. These are Heliopan's although I have one Leica IR filter. Comparing them it appears the Heliopan's are much better multicoated against stray reflection and I read--as much as you can believe what you read😀 --that they are also more resistant. Still, they're so expensive and so essential that rather than buy spares, at this point I just put my MRC UV filters back on over the IR filters (OK, OK, flame away...but until I actually see a reason to take them off they're staying on!). As for coding, at this point I haven't gone there. I understand that the firmware is tuned to the Leica brand filters so perhaps whenever I get my 2 free ones, along with the one I already have, I'll code my 35mm and under lenses and use Leica filters on them. But I have no intention of going into the menu and switching from ON+UV/IR to OFF and back each time I change lenses. I've tried all 3 settings and there's no difference with uncoded lenses. I haven't found any of my lenses have a screw near the code reader, but if that happened I'd fill the screwhead with white paint and the reader would then ignore it.