This is part of a series called Eight Questions to Ask About Your Tech Debt
The main thing to keep in mind is this diagram (described in the introduction):
The next question we’ll cover is on Size: If we knew exactly what to do and there were no coding unknowns at all, how long would the tech debt fix take?
Size is getting at how much it will cost to pay down the tech debt. As a cost of paying, it contributes to the Stay Force. That is, if Size is high, you would be less likely to pay it (all things being equal).
Size works with Difficulty (which we’ll cover next) to give an overall sense of the estimate. Size gives us the magnitude and Difficulty is more about the error bar. This separation of magnitude and risk is common in estimating techniques. At this planning level, I think just these two factors are enough, but when if you need a more accurate estimate, I recommend looking at Quantified Tasks by Jason C. McDonald.
For a lot of tech debt projects, Size is something easy to track as a code metric. For example, if your tech debt project is to replace all Angular pages with React, then the count of Angular pages is highly correlated with size and can be easily tracked. Doing this makes the effect of your work more visible (see Chapter 9). It’s a good way to share your wins with other engineering teams in your organization.
When the Trello web team started to replace CoffeeScript with TypeScript, there was a periodic message in their slack channel with their current progress. I found this personally motivating even though I was on the iOS team. It made me want to convert more Objective-C to Swift.
If Size is High, Try to Chip Away At It
Many tech debt projects are easy to do in small chunks. If a project is too big to justify doing all at once, then a good way to make some progress is to make a team agreement about it (which increases its misalignment) and then everyone should do a little bit when they can. If you can’t get an agreement, but personally feel strongly about it (like I did with compiler warnings), then “Be the change you seek” and do a little bit at a time when you are waiting for a PR (see Chapter 13) or in other self-directed time (see Chapter 14).
(you can read Chapters 1-19 of Swimming in Tech Debt online: https://helpthisbook.com/lou-franco/swimming-in-tech-debt)
Next: #4 Difficulty