The start date for counting is often from the filing date and not the tax year. I keep most records 7 years. And there are some items, when audited, that can trigger a further lookback. You will want to evaluate the type of work you do and what that entails. I was cleaning out a preparer's storage unit and contacting the clients with what looked to me to have significant original records stored there, and one told me for certain they had copies of everything. Guess who contacted me in the next 6 months, looking for their original banking records?