Feature flags are release tools, not storage units. They let teams decouple deploy from launch, test behavior with smaller groups, and reverse a risky change quickly. The trouble begins when nobody removes them.
An old flag is a second product path. Enough old flags become a maze.
Add removal when you add rollout
Every flag should have an owner, a purpose, and an expected removal date. The date can move, but it should exist. A flag created without an expiration plan is already halfway to becoming permanent infrastructure.
This metadata belongs beside the flag definition, not in a meeting note.
Separate ops flags from product flags
Operational kill switches may live longer because they protect the system. Product rollout flags should be shorter-lived. Mixing the two makes cleanup harder because every flag starts to feel critical.
Name them differently and review them differently.
Make cleanup visible
Add a small recurring flag review to release planning. List stale flags, owners, and the code paths they still guard. Removing a flag is not glamorous, but it reduces test complexity and makes future releases easier to reason about.
The best feature flag is the one that helped you ship and then disappeared.
