Wayne Z: "Tax" and "Penalties" are two separate things.
Tax – You always pay tax on a withdrawal from pretax 401k account. Always.
Penalties – If you are over 59 1/2 years old, you do not have to pay the 10% penalty.
Age 59 1/2
Never. Since the contributions were made tax-free, it doesn't mean it's tax-free forever. If you withdraw funds, it's taxable. If you reach 70 and one half years old, you MUST start withdrawing and those withdrawings are taxed.
Visit IRS GOV website for actual info free
At pensionable age, That is what it is for. Not to satisfy a current whim!