If my product passed CE EMC testing once, am I covered for all future revisions?

No. CE compliance is tied to the specific configuration that was tested and documented. Any change that can affect electromagnetic emissions, immunity, safety, or radio performance can invalidate the original test basis. Hardware revisions, enclosure changes, power supply substitutions, firmware changes that alter clocking or duty cycle, and antenna changes for radio products can all materially change EMC behavior. When changes occur, the manufacturer must assess whether the original test evidence remains valid or whether partial or full retesting is required. Treating CE as a one-time event instead of a lifecycle obligation is how products drift out of compliance without anyone noticing.