A redeemable coupon can only be redeemed once per end user.
We save the information about a coupon's redeem status in our system to protect the coupon from abuse. So it does not matter if you refresh your browser or open the eventbaxx again.
When it comes to code coupons, the setting of the partner website is crucial. Depending on this setting they can be redeemed more than once.
Common codes usually can be redeemed several times - personal codes only once.
You are not sure about the difference between a personal and a common code? Then check this article.
After your coupon expired it is not displayed in the eventbaxx any more and therefor can not be redeemed.