Shipping less, noticing more
Making room for the work that does not fit on a roadmap.
The most useful thing I did last quarter was not on any roadmap. It was two days spent reading logs with no hypothesis, which turned into the fix for something nobody had filed a ticket about.
Slack is not waste
A schedule packed to capacity has no room to notice anything. Every hour is already committed to a thing that was decided weeks ago by someone with less information than you have now.
The argument against slack is that it looks like idleness on a burndown chart. The argument for it is every good decision you have ever made about what to build next.
Noticing is a skill
It also atrophies. If you spend six months only executing tickets, you get worse at seeing the thing sideways of the ticket — and that peripheral vision is most of what seniority actually is.