It depends on the document. Junk mail, receipts and credit card statements can be disposed of fairly quickly. If you pay for things using a debit or credit card, keep the receipts until you can make sure they jibe with your credit card or checking statements, then you can throw both away.
Many experts say to keep bank statements, pay stubs, phone and utility bills, and automobile bills for a year or so. Tax-related receipts like business expenses and charitable contributions belong in this category too.
Long-term storage is for tax-related documents like W-2s, expenses, etc. The IRS generally has three years to audit you, although they can go back farther if they believe you’ve seriously understated your income.
Keep things like marriage and birth certificates, passports, Social Security cards, wills, death certificates and titles in a safe place, like a fireproof safe. You might also keep a household inventory in the safe, or even a video of all your home’s inventory.