Why Printed Codes Have a Lifetime
A printed QR code is ink on a surface, and both degrade. Sunlight fades ink, rain and cleaning chemicals attack it, and feet, hands, and machinery abrade it. Scanners tolerate some damage thanks to error correction, but once enough modules are unreadable the code fails — often gradually, scanning slowly or only at close range first. Planning a replacement date before that happens is cheaper than discovering a dead code on a sign that has been failing for months.
How to use the estimate
Pick the material you actually plan to print on, the environment the code will really live in, and the lamination you will actually pay for. Use the replacement date to diary a reprint, and use the mid-life inspection date to test-scan the code in place. If a code already scans poorly at inspection, replace it then rather than waiting for the planned date.
