We go to the pool often, and when our entire family applies sunblock to their faces/bodies (plus reapplications), we use almost an entire bottle! I need to buy sunblock by the case! We seriously go through a bottle a week since we put it on the kids every single day from head to toe (since Charlie is in camp), and we're usually out all day on the weekends.

I switched from Thinkbaby to Blue Lizard because it was more inexpensive (and I like it just as much, if not better).

How long does sunblock last for you?