Tier credits are simply a means of tracking progress towards increased tier status and additional player benefits. Qualifying period for earning tier credits is twice per year (every six months). Tier credits are not points nor can they be redeemed for cash, comps or slot view play.
Additionally, every Tier Credit qualifying period is extended by one week. This means that not only do you get an extra week of benefits, but you also receive an extra week of earning at the beginning of each qualifying period as well as the end of each qualifying period.
View your tier credit balance at MyInsider.com, any kiosk, or the Island View Player's Club