Think twice before tossing those credit card offers or monthly bills in the trash (or recycling bin). Thieves regularly practice “dumpster diving” — picking through your trash at night or when you’re not at home in hopes of finding information they can use to steal your identity.

For this reason, buying a paper shredder to destroy documents that contain sensitive information could be a wise investment. But what should you shred? And what documents should you keep instead of tossing? Heed this advice. 

What to shred

According to the Washington State Office of the Attorney General, your privacy may be what's shredded if you carelessly throw away:

  • utility bills
  • ATM receipts
  • bank statements
  • credit card statements
  • voided checks
  • employee pay stubs and records
  • copies of your birth certificate
  • legal and insurance documents
  • expired passports
  • resumes
  • used airline tickets
  • signed contracts

What to keep

In general you should shred all mail and paperwork that includes account numbers, birth dates, passwords, pin numbers, signatures or social security numbers. But don't go too crazy with the shredder. Tthere are some things you need to hold onto.

Here's what the U.S. government says you should keep forever (or at least until the information is outdated). Store them in a fire-safe box or a safe deposit box at a local bank:

  • original birth or marriage certificate
  • college transcripts and diplomas
  • divorce decrees
  • passports
  • mortgage documents and real estate deeds
  • vehicle titles
  • education or military records
  • social security cards
  • life insurance policies
  • wills and trusts
  • powers of attorney
  • warranties

These items should be kept, but you can shred them once you have confirmation the bank or other financial institution has cleared the transaction, according to the Washington State Office of the Attorney General:

  • bank and investing statements
  • cancelled personal checks
  • credit card statements
  • general receipts that hold no tax or warranty implications
  • pay stubs

Once a year, shred your health, car and homeowners insurance documentation, since those policies are renewed on an annual basis.

Finally, keep your tax documents — but not forever. When to shred them depends on your situation. In general, the IRS can audit your return up to three years after the filing date. If you underreport your gross income by 25 percent or more, then the statute of limitations on your return increases to 6 years. The U.S. government says a good rule of thumb is to keep your tax records (the returns themselves and the records that back up the return) for seven years, one year past the six-year window. If, however, you file a fraudulent return or fail to file one altogether, you should keep your records indefinitely because the statute of limitations doesn't start until you eventually file a return.

What type of shredder to buy

The most important factor to consider is the cut pattern. Look for a shredder that crosscuts (cuts in two directions). Some shredders cut only in strips and, although it would be a time-consuming puzzle, an identity thief could piece those strips back together. A shredder that turns your documents into little bits of paper is the best option.

Some shredders are not equipped to handle plastic. That would be a consideration if you want to slice up credit cards or CDs.

The larger, more expensive shredders will be able to handle more documents at a time and will need to be emptied less often. Some even have automated feeders that slowly shred 100 sheets of paper at a time, freeing you up for other tasks while the shredder does its work.

In come cases, such as a loved one passing away, you may be faced with massive amounts of shredding. In this case it may be a more prudent use of time to take the documents to a local shredding facility or contact a service that sends a shredding truck to your home.

Keep paperwork to a minimum

Of course, with all this mail and paperwork comes the problem of clutter. Take advantage of technology, like electronic billing and banking or scanning documents into your computer before shredding them, to keep your information secure and reduce piles around the house.

In the end, all you want the dumpster divers to find are tiny shredded pieces of your life. 

Brian Fourman is a stay-at-home dad who writes about home safety and personal finance.