I'm very careful to measure my ingredients when I bake. Baked items are often sensitive that way; they can be thrown off by the wrong amount of salt, baking powder, or soda.
When I cook, I can "eyeball it" like Rachael Ray, and it's usually not a problem.
But one hint that has stuck with me from my reading of
The Complete Tightwad Gazette: Promoting Thrift as a Viable Alternative Lifestyle
is that you should take the time to measure your household cleaners.
Chances are, if you just splash some Lysol into your bucket of water, you'll use more than if you measure the 1/4 cup recommended per gallon.
Also, if you measure, you may find that you can do the job with less. I never use the full recommended amount of laundry detergent or dishwasher soap. By starting with the recommended amount and using a little less on each load, I've found the minimum that works for me (based on the kind of water we have here).
Measure it--use less--save money! Works for me.