Establish known size to known definition of done for all defects, research, new features, etc. For example determine what a typical size 2 work no matter what kind of work it is:

• Defect to known, typical Definition of Done
• New feature to known, typical Definition of Done
• Release Sprint item to known, typical Definition of Done
• Research Item to known, typical Definition of Done

This approach is a variation on both Establish a Keystone User Story and Establish Points Guidelines for Each Point Value

This, again, can help with consistency.