One of the many debates personal finance nerds love to talk about is whether to pay off student loans or invest? We go back and forth. Invest or pay off debt? Pay off debt or invest? Do both maybe? IDK. I used to have a hard stance on this one but I've loosened it in resent years. But I will tell you my personal opinion: I think you should pay off your student loans before you get a big head about investing for retirement. There, I said it. It’s how I feel, it’s the truth I lived, and here’s why:…