Sustainable - good quality moats making it hard for the competition
Network effects - each new customer adds value to others, meaning viral referral patterns
Predictability - subscriptions being one of the best examples
Customer lock-in - it’s hard and/or expensive to move to a competitor
Gross margin levels - i.e. each dollar sold generates significant +ve cashflow
No customer dependency - i.e. no customer contributing more than 10% rev
No partner dependency - your company’s destiny is not tied to another’s management team
I use this to rate the health of revenue regardless of exit plans.