If you’re contributing $150 per month to retirement, your account could hold to up $78,000 after 20 years**. Over half of that (about $42,000) is investment earnings–the money your contributions have generated just by being in the account. With a Roth IRA, you won’t need to pay taxes when you take out any of that $78,000. With a traditional IRA, you’re taxed on the entire sum of $78,000.