I just bought a bottle. I was going to buy the small pint bottle, but it has no automatic measuring cup. The large size has the neat spout where you can pour 1/4, 1/2, 3/4, 1, and 2 ounces. Since I am only storing 1.24 gallons at a time, the 1/2 oz measuring cup on the bottle is really useful, so I ended up getting the larger size. $10 versus $16 for twice the amount. So that is the main advantage of the larger size. On the label, it says good for 2 years, but the manufacturers are always conservative about shelf like. It says petroleum distillates on the label so supposedly no VOCs to evaporate so I would think it will last a long time with the cap on.