If you get into a top-tier school, like Harvard, you must go. But what about second- and third-tier schools? It's not always a no-brainer based on the cost. Student loans can be crushing, and you need to factor in your return on investment via earnings potential, especially in a world where student graduates are netting $55K a year for sales jobs while high school dropouts receive offers for $110K for trucking jobs. Luckily, I have a rubric to help you determine whether you can (and should) enroll in college…