You really can't protect yourself completely. It is the right thing to do to give at least a two week notice when leaving a company and if they decide to let you go earlier, that's their call and right as the employer (or at least it should be). You just have to deal with what happens. Having some money stashed away (emergency fund as Dave Ramsey calls it) can make this a minor issue. It's not necessarily easy but it gives you some stability so your not living paycheck to paycheck.