I always make more food than needed. (Portions? What are those?) I think it’s hereditary, as my mom made enough food for at least two or three times the number of guests she was expecting. I was always taught that running out of food at a dinner party was the absolute worst thing that could happen. Good thing that I like leftovers - my freezer is usually full of them.
As far as keeping track of all those leftovers, there a lot of fancy labels out there, but I love using a piece of duct tape and a sharpie. It sticks and stays stuck, even in the freezer, and in my experience, it easily peels off without sticky residue to clean up, even after a cycle in the dishwasher (although it’s best to let it cool down before peeling). To top it all off, duct tape is inexpensive and useful for so many other things.
If I ever find myself with a food-related business, I’m going to call it "Duct Tape Foods" and use duct tape for labeling. Kinda joking, kinda serious :)