I know I've bought many of those salad bag mixes, only to end up throwing them in the trash when they start rotting 3.2 seconds after I open the bag. These bags of lettuce, in any variety, are not your friend. Some of the ones that last a longer time are the ones that are a "softer" variety of greens. The problem with those, is they supply you with ZERO crunch factor. Mama needs some crunch factor.
So, considering all of these, you need to buy the 3-pack of Romaine hearts, and here is what you're gonna do. You're gonna drop less than $3 on a 3-pack. You're gonna cut the butts off those suckers. You're gonna nestle the leaves in some paper towels in a plastic container. And you're gonna grab a leaf for a sandwich. Or maybe you're gonna grab a few leaves, quickly hand shread them, and make a salad.
If you keep Romaine lettuce as I've instructed you, you're Romaine lettuce will be awesome for a week. At least. If you only break down one heart at a time and leave the other 2 in the bag, You're gonna be good for at least 2 weeks.
No more tossing lettuce in the trash left and right. No more wilty, sad lettuce. You've got lettuce that has a lot of vibrant green and a lot of crunch. But the awesome of Romaine doesn't stop there. You can regrow your freaking Romaine. I'm not even kidding. Stick that Romaine butt in a cup of water, sit it in a window, and watch it grow.