Prevent mney mistakes today, and save big bucks tomorrow. Print Email PagesPrevious 14 of 18 Next View All 7. When you leave your job, you cash out all or part of your 401(k) HOW IT HURTS: You have to pay stiff penalties if you are younger than 59½, and you lose out on substantial future earnings. Related Links Save Money on Your Major Bills How to Save More Cash (Now and in the Future!) Got bad credit? Bail yourself out.