Yes, I do it fairly regularly. Your limitation is how many times in 30/60/90 days a particular partner permits a redemption, if they put any time limitation at all. Some partners will permit more than one redemption in the specified time period as long as each redemption is for a different reward level, i.e. $10 GC and $25 GC might be OK, but 2 redemptions for $25 each is not.