Hi Kathleen:
I don't give extra credit. I once did and over the years found that it really doesn't contribute to much benefit to the student, other than adding points, and less about learning.
The old expression "The road to Hell is lined with good intentions" applies here. In an effort to help students, all kinds of problems can arise.
A few bonus points on an exam, or maybe dropping the lowest quiz score if the class has a lot of quizzes - these seem reasonable and consistent with demonstrating knowledge attained vs simply added points to achieve a grade.
Who wants an "A" student who can't function in a work setting?
Regards, Barry