What's the biggest churn signal you wish you'd caught earlier?

Most B2B SaaS founders I talk to have a story — a customer who left that they could have saved if they'd noticed the warning signs a few weeks earlier. Login frequency dropping. Support tickets turning negative. Emails going unopened.

EZER was built to catch and act on exactly these signals automatically. Curious what patterns the community has seen — what were the early warning signs you missed before a customer churned?