All contacts, including contact credits, expire six months from the date the original contact credit was granted.
Example:
On January 1, 30 new contacts are distributed per your Standard subscription plan and renewal date. On July 1, six months from the date the contacts were distributed, any remaining contacts will expire.
If you use some of your contacts but also earn credits back due to positive responses from job seekers. On July 1, six months after the original contacts were distributed, any earned contacts (contact credits) will also expire.