Skip using your employer-sponsored 401(k) retirement plan? To many experts, that would be as daft as torching a wad of $100 bills. Why reject a tax-deferred savings plan that often boasts matching contributions from one’s employer? Evidently, plenty of people wouldn’t: According to a recent Charles Schwab survey of 401(k) plan participants, 87% of respondents deem a 401(k) to be a “must have” benefit.