A jar of peanut butter that used to last at least a month in my single life now disappears in just one week. I don't ever want to be the kind of partner who hides the peanut butter jar. Like making peanut butter sauce with the teeny bit left in the bottom of each jar. Warm water is best because it helps to loosen the nut butter more quickly, and generally equal parts nut butter to liquid is the best ratio. And luckily, now I've learned to always have a backup jar of peanut butter in the house.