Kind of random, but I thought I’d make a list of how long these common household items take to get used up.  These are pretty much estimates that are just based on my own usage habits.

Item Time to Consume (months)
Bar of Soap (1” x 3” x 4” approx.) 2.5 – 3
Bottle of Shampoo (355 mL) 3
Toothpaste (170 mL) 5

Hmm so taking the lifetimes of all these items, the lowest common factor is 15.  For every 3 tubes of toothpaste, I should buy 5 bars of soap and 5 bottles of shampoo.  Assuming that I start using all of these at the same time that is.

Looking at these numbers puts things into perspective.  I always felt like I’ve been replacing these same items over and over, but I guess I just lost track of how long it had already been since I last replaced it.