There’s an art to designing the perfect college schedule. It’s a delicate balance between leaving time for your responsibilities while leaving ample time for a total lack of responsibility. It’s a way of spacing things out enough that you don’t overburden yourself, but keeping it tightly clustered enough that you can have long stretches of no work at all. Your perfect schedule is a set of fingerprints, totally unique to you. That being said, there’s a handful of horrible mistakes I made (or at least observed) when mapping out that elusive perfect schedule, so here’s a handful of caveats of things that might sound like a good idea, but really, really aren’t.

Don’t cluster your classes together (too much). Here’s something that at first seems like a bad idea, then seems like a counter-intuitive great idea. Stick with your first instinct. Some people will try to cram all of their classes into as few blocks as possible, but that’s just a one-way ticket to exhaustion. The more you cluster classes, the less downtime you’ll have to process information after the class ends.

Avoid classes at dinner time. My freshman year I took a number of 6:30 pm classes. Big mistake. While the idea of “Hey, I get to sleep in as late as I want” sounds pretty great at first, double check which hours you’re sacrificing in order to sleep more. Which hours would you rather have to yourself? 8-10 am — where everyone is either in class or still asleep — or 6:30 to 8 — when everyone’s either eating or socializing? You’ll just end up having a bunch of early-bird dinners by yourself.

If you must take a late night class, make sure it’s not art history. I took one night-time art history class and it was AWFUL. Why? Because once the class starts, the lights go off and the slide projector comes on. An hour and a half later they come back on, jarring half the class awake again. I wish I’d saved some of my notes from that class, since there was always a very clearly identifiable point where my notes stopped being recognizable as words.

8 a.m. classes aren’t as bad as they seem. (They’re worse.) I’m sure there are some very disciplined people out there who can handle these, but the average college student should stay far, far away. The problem isn’t waking up early. The problem is that college life leads to a lot of unexpected late nights, whether you’re partying or paper-writing. It’s better not to have that rub up against your classes. You woke up ridiculously early in the morning for high school. Once you start working, you’ll most likely start the day at 9 am.  Cherish the years when you can start your day at 10 or 11 am.

Don’t take Fridays off. One of the Holy Grails of college scheduling is the permanent three-day weekend. But it’s not all it’s cracked up to be. It’s too tough to be social on a Friday by yourself, since most of your friends will still be in class. It’s even tougher to be productive, since, no matter how you try to trick your brain, it’s still Friday. A better approach? Take Monday off. It’s trickier to pull off, but if you do, you’ll feel like you added an extra day to the week. The weekend raps up, every one gets back to work, but you still have a day to yourself to sleep in late and prep for the rest of week.