For the future, Apple has a short-term return policy (14 days I think) where they'll take a device back for any reason, no questions asked, full refund. So even

For the future, Apple has a short-term return policy (14 days I think) where they'll take a device back for any reason, no questions asked, full refund. So even if it's an intermittent problem that's hard to demonstrate, if you feel like there's something wrong with your device, you can just take it in and get a new one in that time period no matter what.