At my university, you're only allowed to take so many credits over the amount needed for a degree (128). In my program (business), they'd stop you front taking any further classes. The university would also charge you out-of-state tuition if you pass the set amount. That's how I knew I was ready to graduate
I'm happy to be out of undergrad, though. My school was pretty good with preparing students for the "real world," as a big chunk of our students are non-traditional.