Making decisions - the Last Responsible Moment

Apr 6, 2024 architecture

We sometimes get stuck in the mud making decisions or over-planning - there's a balance
to be had around big design up front.

If we wait longer we will gather more information and context so we can make more informed decisions.

  • Deciding too early is a risk.
  • Waiting too long and accumulating technical debt, deciding too late is also a risk.

There is a middle ground called the Last Responsible Moment where the cost of waiting any longer detracts
from the benefit of pausing and gathering more information.

Last Responsible Moment

At JustEat, I was taught to wait and watch a little bit. Sometimes I would rush into trying to fix a problem
earlier than waiting for the systems to react and scale up. Hanging back and letting the services settle
often more than not solved the problem. Also if there was a problem it was better to fix it the next day
when everyone was fresh eyed, and rely upon the call centre to handle the edge case rather than try and change
a production system during peak usage hours, after a full day of work when you're tired and everyone else
in your team have gone home.