Before you say yes to any position—no matter how badly you need a paycheck or how long you’ve been on the job market—think first. Take out a calculator and spend some time making a rough budget for the next few months or the next few years. Factor in your monthly living expenses, your financial goals, and the value of each hour of your time. Don’t accept any offer before you’ve thought through the implications for your own life and lives of those who depend on you. When it’s time to tackle the salary negotiation process, here are five common mistakes that can easily trip you up and set you back.