These are great for leftovers - especially when having a dinner party. They are great for that because I tend to have a LOT of leftovers after parties, and can't possible eat it all myself before it goes bad. With these, I can give people their own leftovers, and 1) they are pleased that they don't have have to use messy plates with foil and 2) I am pleased that I don't have to give people the more expensive food containers. I also don't really have to worry if they can be used in the dishwasher (although I have tested and when I kept them on the top rack they were fine). I also don't have to worry if they top doesn't really fit correctly (although I have not yet encountered that problem).