Using your iPhone on a poor, weak, or spotty Wi-Fi is not only frustrating. It could also have a detrimental effect on battery life. But there’s a fix, for flaky Wi-Fi at least. You can tell your iPhone to use cellular data to make up the shortfall, giving you smooth internet access, at the expense of some cellular data use. It’s called Wi-Fi Assist, and it could be the answer to all of life’s problems.