For example, if Card A has 5% off gas for January through March, 5% off entertainment for April through June, 5% off dining out for July through September, and 5% off groceries for October through December, place that info on the sticker; do this for each card. This way, when you’re about to purchase something, you can easily see which card to use for that purchase — without having to open up your smartphone to check an app or look online. It’s “an interesting, low-tech way” to do this, says Schulz.