If you love salads, you probably have lettuce sitting in the refrigerator. It’s a water dense food so it can spoil quickly but I’ve found a useful tip that keeps lettuce fresh longer.
When you’re washing and preparing it, remove any of the white membranes that run down the middle of the leaf. That’s the most water dense part so it usually spoils here first, discolors and tends to spoil the rest of the lettuce at record speed. If you really enjoy eating it, serve it first and keep the greener pieces for future salads.