Regarding how to prioritize a bug fix

Today I read a very interesting article regarding regression testing.

Details please check http://www.ericsink.com/articles/Four_Questions.html

Every bug you found in your application, before you work on a fix, you should ask yourself below four questions:

Question One: When this bug happens, how bad is the impact? (Severity)

Question Two: How often does this bug happen? (Frequency)

Question Three: How much effort would be required to fix this bug? (Cost)

Question Four: What is the risk of fixing this bug? (Risk)