I've never completely understood what goes into a credit score. 30 years ago I was afraid to check on my score because I knew it sucked and I really just didn't want to know just how bad it was. I guess it got better over time and for the past 10 years or so Credit Karma reminds me via email every week or so of all the good things I can do with a score in the 830's.
I don't think the score has much to do with the amount of credit card debt, mortgages, loans, etc., but rather what percentage of available credit you routinely use and the timeliness of your payments. I think my fairly high "exceptional" rating is because we have no debt and routinely keep credit card purchases under 3% of available credit.
At some point last year mine dropped over 20 points one month but then recovered the next month to its usual range and I've never been able to figure out why.