Had to deal with fingerprinting for a couple work gigs. One thing that really messed up the process was me putting in bathroom tile. Between me using my fingers to smooth the grout and other manhandling/construction - I apparently wore off the prints enough to cause issues with the reader.
Same thing happens to me when manually sanding and doing any concrete work without gloves. The sandpaper and concrete acid remove enough of my fingerprint so as to not be recognizable anymore.
