Have you ever felt when you looked in your fridge that you had no idea which leftover corn was from yesterday and which was from last week? Or went to grab lunch and have to dig through the containers to find what you are looking for?
When we remodeled our kitchen, the plan was to have one section of cabinet painted with chalkboard paint. Then plan fell through since we had 2 different painters, and it slipped through the cracks. My mom, however, bought me some chalkboard pens, which I've found a different use for: labeling containers of leftover good!
I just write right on the lids. When they go through the dishwasher after the food is gone, it comes right off! It's worked great for us! Much less food wasted due to unknown cook date. :)