The tools of his trade were a 
The Realist Idealist: Trying to undress my 'water footprint'That's about 10 times more water per day than I use to shower, 
When should I change my Water-bottle, Tooth brush, Shaving brush, shoes and socks?
Toothbrush is the one you really need to change most often, especially when you have been sick, if you haven't been sick, you need to change it once a month, bacteria grows well on a damp brush and the bristles become too soft and misaligned to correctly brush your teeth. Shaving brush, just change the blade, so you don't let it get dull, which increases chances of hair follicles getting curled and caught under the skin. The water bottle, as long as that is washed thoroughly and not shared, I don't see a real necessity to change. Socks, if they show wear, fabric starts getting thin near the foot soles. May sure they stay clean. Shoes, the soles are most important, as the feet sweat and another breeding ground for bacteria, and athlete's foot, and odors.
Just think of it as you would your hair, trimmed and conditioned, to prevent breakage, split ends, etc.
