WASHINGTON (AP) — The Internal Revenue Service has a message for taxpayers eager to learn the status of their tax refund: Please don’t check the IRS website every five minutes — once a day is enough.

The IRS says its “Where’s my refund?” website and smartphone app are being overwhelmed by eager taxpayers. The agency says its systems are only updated once a day, usually overnight, and the same information is available the website, the IRS2go smartphone app and IRS toll-free phone lines.

To avoid delays, the agency says the best time to check on refunds is evening and weekends.

The IRS says nine out of 10 taxpayers typically receive refunds in less than 21 days when they file returns online and get refunds deposited directly into bank accounts.