The basic retention period. Federal tax return substantiation is generally three years from the later of the tax return filing due date OR the actual filing date.

State guidelines could be different. Understand your state and local audit timelines. Often states can review tax returns after your federal return is officially closed to a potential audit. When in doubt figure six months to a year after your federal tax filing retention period.

Keep some things forever. Some items should be kept indefinitely. These include, but are not limited to: copies of your 1040 tax return, major asset purchases and sales (home mortgage, home closing documents, documentation for stock and investment transactions, major asset purchases and sales documents, insurance documentation, and birth/death/marriage certificates).

Keep valuable item receipts. Keep records of any other valuable items purchased. This includes jewelry and other collectibles. You will need this to substantiate any gains or losses when you sell the item.

Finding the cost of stocks is easier...and trickier. Stock and investment companies are now required to report the cost of your investments to the IRS. So you will not need to dig around for old transaction information to prove what you paid for your investment. On the other hand, any errors on your investment statement also get sent to the IRS, so make sure the information provided is correct or it may create an audit trigger.

Digital asset documents must also be saved. If you buy or sell something using cryptocurrency, you must retain all related documents that confirm the purchase date, sales date, and cost.

Others may want your documentation. You may need records for non-tax related purposes. Copies of divorce decrees, records of insurance, and home sales closing paperwork are common examples of documents needed for other reasons.

Federal recordkeeping guidelines could become longer. Federal guidelines for record retention are generally 3 years. However, errors on your tax return for more than 25% of the tax obligation require record retention of 6 years. If fraud is determined, the record holding period is indefinite.