Use the cards for recipes carry some with me all the time to jot down notes about items needed where the best price also for names & addresses of new people I meet.
I'm constantly writing notes and 'to-do' lists and I find the 3x5 size very convenient to keep in a shirt or jacket pocket for a quick review or a short note to myself.
I use these regularly as flashcards for my college classes and I love them they are sturdy and I love how they have recycled content! The only problem I had with them is that the lines are too wide and I can't fit that much information onto them.