How do you tell if a quiet month was actually productive or just wasted time?

Sometimes you spend weeks fixing backlogs clearing debt or narrowing focus without shipping a single new feature. Visible progress looks like zero on the dashboard, but the underlying product gets way stronger.

It's easy to feel guilty when there's nothing new to announce or post in a changelog even though that cleanup work was totally necessary.

How do you measure progress during periods where you're fixing internal stuff instead of launching new features?