I’v only ever had one rule, and I think it covers just about everything.
“TRUST NO ONE, BELIEVE NOTHING UNTIL PROVEN TO YOUR OWN SATISFACTION”.
Seems to work just fine for me.
My unwritten rule came from my grandfather, and he didn’t mean it as a negative.
“Nothing lasts forever!”
His belief was to enjoy what you have today. Because tomorrow they, it or you might not be around.