I wait till avocados are on sale then I let them ripen and make a large batch of guacamole and freeze it in ice cube trays. These are then stored in a freezer zip lock bag, and when needed I one or two cubes and let them defrost at room temperature or carefully zap them a few seconds at a time in the microwave. There is so much oil in them that it doesn't take long to soften. Don't put tomatoes in guacamole you're going to freeze, they are weird when it thaws.