The metric that actually matters in a small service business never seems to make it onto a dashboard

I have run a software company, a care home, and a cafe at different points, sometimes more than one at once. None of the numbers I actually watched closely lived in a report. Revenue and margin mattered, obviously, but the thing that actually kept me up was smaller than that, a client who had gone quiet, a shift that was one call away from falling apart, a lead I told myself I would follow up with and then did not. None of that shows up on a P&L until it already cost something.

Curious how other people running a small or solo operation actually track that layer. Do you keep it in your head, write it down somewhere, or has anyone found something that actually surfaces it before it becomes a problem?