What percentage of my husband's check should go into a 401 k? (he gets paid weekly)?

401K plans that are provided by companies are notoriously bad at investing, possibly because they don't really need to impress their customers. The plan is chosen by the company based on what they can afford, not on which one does the best job of money management. Tell hubby to skip the weekly deductions, keep the extra money in a savings account and then have payroll put part or all of his last paycheck of the year into the 401K.