At Trello, on the mobile team, we had a formal way of allocating engineering time to either working on PM-led or Engineering-led initiatives.

A PM-led initiative was something that ultimately rolled up to a OKR that was well-understood by the business. The requirements came from the PM and the PM could assess acceptability. An Engineering-led initiative was something like tech debt, changing our dependency package manager, improving CI build times or anything where the requirements came from the team itself and the PM didn’t know or care about it (and neither did anyone outside the team).

So, let’s say we decided the split was 60% on product manager led initiatives and 40% on what we called engineering-led. The split is arbitrary—the EM and PM agreed on what was appropriate for their team and set it for the year.

Then, any individual engineer at any one time (for a couple of sprints) was on either a PM-led project or an Engineering-led project. We did not want a single engineer to be split across PM/Eng-led work. This made it easy to know we were allocating correctly (without having to track time on individual stories or cases).

So, if it was 60/40 and we had 10 engineers, 6 would be on PM-led, and 4 would be on engineering-led at any one time, but it rotated.

This just needed to be mostly right over the course of a year—on any specific month it could be a little off if over the long-term, it matched.  For example, If the PM didn’t have work ready, we could do more engineering-led work temporarily.