Long story short, Costco has an amazing price on pesto, but I find it so hard to use it all before it expires! So, I divide it into smaller jars and freeze it in individual serving sizes for recipes. They defrost so fast (even faster with a little warm water help) and are typically the perfect amount. I try and do this around a month before the expiration date of the pesto, so that I am freezing it fresh and know I have plenty of time to use it once it defrosts.
Also, masking tape is the BEST THING EVER! Perfect label, freezer friendly, and comes off so easily, leaving zero sticky residue behind.