College credits do not have an expiration date, but whether schools choose to accept old credits is at the discretion of the specific school. Some colleges and universities, like The American College, do not accept credits older than five years.
Once a college course is completed, the credit hours do not expire. Credits may be transferred to another program or another school, provided that school accepts them. A school is not forced to accept credits from another college or university, nor is a college forced to accept credit hours earned through one program when a student transfers to another course of study.