Things to think about when defining test regression scope

How much regression do we do?  How do we select the right balance?

These are the things I consider:

Recent: new features, new areas of code are more vulnerable
Core: essential functions must continue to work
Risk: some areas of an application pose more risk
Configuration sensitive: code that’s dependent on environment settings can be vulnerable
Repaired: bug fixes can introduce new issues
Chronic: some areas in an application may be perpetually sensitive to breaking