Growth is good, right? Sustainable growth is. Non-sustainable growth is, well, not so good.

Any project will have some mix of maintenance and new feature development. When it first starts, it will be all new feature development and no maintenance.

Naturally each new feature adds weight/inertia to a project and some maintenance. If you’re not careful, the maintenance share of your time will grow to the point where your previous pace of feature development is no longer sustainable.

This is especially dangerous for a start-up whose existence depends on being able to innovate quickly. Should the maintenance (or technical debt) become too big, it will stifle that and their innovation pace flattens.