Buffer

Estimates can be wrong. A buffer gives the schedule room for that uncertainty: a block of time you leave available so a small delay doesn't immediately move the launch date.

One approach is to keep task estimates separate from the buffer and make both visible. Place the buffer at the end of a risky chain of dependencies, before the milestone it protects. The team can then see how much of it a delay consumes.

If the work fills every day up to the deadline, check what happens when an estimate runs over. Agree on the buffer with the team so everyone knows what time is available.