Time is a prerequisite; the average age of accounts must be high, proving long-term reliability.

Credit Scores, Disaster Risk, and Home Insurance Affordability - NBER

A single late payment can derail a perfect score for seven years.

Frequent applications for new loans create "hard inquiries" that temporarily suppress scores. Beyond the Number: Why It Matters

The highest credit score possible is 850, a rare achievement reached by less than 2% of consumers. The Illusion of Perfection

Elite scorers typically use less than 10%—and often as little as 1% to 3%—of their available credit limits.