For both Ez and BudURL when you exhaust the number of clicks of an individual link, the link will continue to redirect and will always work unless you remove the link. What you lose is the Premium Click Stat information that gives you more insight into where your traffic is coming. Here is more info to what Premium Click Stats are on Ez:

http://support.liveoak360.com/answers/531-what-are-premium-click-stats

Hope that helps!

Mike Saenz