A pro-con list is usually the place to start when it comes to tough decisions. These lists are nothing new, but there's an interesting way to make them more useful: quantify every item on the list, then add it all up.
In his book, Get Smarter: Life and Business Lessons entrepreneur Seymour Schulich has an effective way of making decisions based on a pro-con list. Instead of just writing down a standard list of things to mull over, you give a numeric value of importance to each item. He explains the process:
On one sheet of paper, list all the positive things you can about the issue in question, then give each one a score from zero to ten -- the higher the score, the more important it is to you. On another sheet, list the negative points, and score them from zero to ten -- only this time, ten means it's a major drawback...If the positive score is at least double the negative score, you should do it -- whatever "it" is. But if the positives don't outweigh the negatives by that two-to-one ratio, don't do it, or at least think twice about it.
I actually use a method similar to this, but I don't use Schulich's double metric for making the decision. My pro number simply has to surpass the con number, but I think Schulich's rule may actually be a better gauge, because it accounts for optimism bias -- our habit of exaggerating the upside of something.
You know your own tendencies, so you can adjust your bottom line rule accordingly. Either way, quantifying each item takes an old standby and makes it a little more useful. Check out the full post for more detail.