I wrote another blog post on the SoundCloud Developers blog earlier this year: Managing Unplanned and Support Tasks.
The blog post explains how my team set up a process to deal with a large increase in unplanned and support work by becoming responsible for a larger domain with fewer people as a result of cost cutting.
The process changed how unplanned work gets reported and distributed in the team and how we track and visualize it. It went through multiple iterations and fine tuning and allowed us to surface root causes of unplanned work. By quantifying the time spent we got buy-in to do work that improved the situation substantially. Since introducing the process the team feels empowered to improve the situation which was crucial for sustainability and motivation.