Why blunder traps are not enough
A blunder-trap grid gives a specimen, which conservators need for identification. It does not give coverage, because the traps are read on a schedule and the stores they sit in should not be entered weekly. A monitor with a year-long lure counts every night and reports without the door being opened.
Placement
Stack ends and skirting for silverfish. Plant rooms and the warm side of walls for firebrats. Grey housings sit against concrete, gold against timber in historic rooms, and neither carries a marking a visitor could read.
Reading the count
A low, steady count is background. A rising count on one aisle is a breeding site and a reason to walk that aisle, not the whole store. Keep the sticky traps where a specimen is still needed and move coverage to the gate.