how long do i need to keep documents such as bills?
1 Utility Bills (You can throw out after one year, unless you're using these as a deduction like a home office --then you need to keep them for 3 years after you've filed that tax return).
statements---assuming you are paid in that way---after you check them against your annual W-2 Form. But save cancelled checks that relate directly to an entry on your tax return, and keep all medical bills for 3 years to back up your cancelled checks. The IRS generally keeps records for 6 years.