Certain myths about retirement savings can really hurt in the long run. Here are five you should understand.Number 1, your retirement-plan contributions are locked in until you retire. This isn’t the case, though withdrawing from an IRA means taxes and penalties. You can borrow against your employer’s 401(k) or defined-benefit plan, but you’ll need to pay it back before you leave the company. Hardship loans are possible, but they, too, mean taxes and penalties. Your best bet is a withdrawal from a Roth IRA. 2, if you contribute to a retirement plan at work, you can’t also contribute to a traditional IRA. Tax deductions for traditional IRA contributions may be limited if you also contribute to your employer’s 401(k). But they’re not prohibited as long as your income stays below a certain level. 3, you have to roll over your retirement funds into an IRA when you leave a company. Some retirement funds can be withdrawn or transferred to another account. For example, if you’re 55 or older and retire, you can make penalty-free withdrawals from your 401(k). Some workers younger than 55 can transfer their 401(k) funds from their previous company’s plan to one with a new employer. 4, you should never withdraw the principal from your retirement accounts. It’s not recommended, but you can in a crunch. For retirees, many advisors say it’s safe to withdraw 4% of their accounts per year. Others say 3%. Regardless, the key is tracking expenses and allowing room for emergencies over an extended lifetime. And 5, you’ll spend less money when you retire. Many advisors tell their clients to spend no more than 85% of their pre-retirement income when they stop working. But your costs may be higher, depending on healthcare, hobbies and lifespan.