Have you ever seen toothpaste adds with inch long swirls of toothpaste? You only need a little dab, but they want you to use a lot. I suspect that the same holds true for other products, and I don't want to use more than is absolutely necessary of any of them.
Soft soap dispensers dispense more soap with each stroke of the pump than I usually want. My solution is to make a sleeve around the neck of the pump that restricts the amount the pump will push down. By adjusting the length of the sleeve (cut from vinyl tubing), you adjust the maximum amount of soap that can dispensed.
Since the diameter of the vinyl tubing is too small to fit over the top of the pump, the section to be used needs to be cut down one side with a knife. It is then slipped over the neck of the pump and held in place with a little electrical tape.
Applying the same concept of minimising consumption to other products, one can use squirt-type dispenser caps from other products on things such as hydrogen peroxide bottles to allow more precise application of the product than you get by pouring it from an open bottle.