Identification credits (monthly visitor IDs) do not roll over from month to month. Your monthly identification allotment resets on the 1st of each calendar month, and any unused credits from the previous month are forfeited.
On the 1st of each month:
Who to Contact (contact lookup) credits may function differently depending on your plan type. Some plans allow those credits to carry forward.
Your current monthly usage and remaining identification credits are visible on the main dashboard when logged into app.visualvisitor.com.