Did you know that:
A sharp mower blade is healthier for you lawn. A jagged cut on your lawn opens it up for disease. In normal homeowner type use, a mower blade should be sharpened 2 to 4 times per mowing season. In my shop all mower blades are cleaned, sharpened and precision balanced.
When using your chain saw, the finer the discharge is, the duller the chain is getting. Discharge should be chips, not sawdust.
A dull kitchen knife is more unsafe than a sharp one. You won't be forcing the knife if it is sharp. It's a good idea to have your kitchen knives sharpened 2 to 3 times a year.
Reel mowers give your small yard a cleaner cut than a regular rotary mower if it is sharp and properly adjusted. In normal use a reel mower needs sharpening about every 2 years.
Electric and gas hedge trimmers need sharpening to assure they cut quickly and cleanly. If you notice it is "chewing" at the branches, it needs sharpening.