How Long Do String Trimmers Usually Last?

String trimmers, also known as line trimmers and weed whackers, came into the world when George Ballas invented the Weed Eater in 1972. Whatever you call it, buying a string trimmer is one of the best decisions you can make for your home's outdoor maintenance. It can eat weeds, of course, but it can also clear heavy brush, edge lawns, and even substitute for a lawn mower in a pinch. This tool is a great investment, but before charging one to your credit card, it's just good buyer's practice to ask how long you can expect it to last. Lawn professionals and product reviewers generally agree that trimmers last from five to 10 years, but longevity depends on several factors. 

The first factor is the power source. String trimmers can be gas-powered or electric, and while corded models were common in the past, these days most electric ones are cordless. When a battery enters the equation, its expected lifespan is a cost factor, because new batteries aren't cheap. Under normal use, you can probably expect your string trimmer battery to last about five years. 

You can extend battery life by proper storage and charging techniques. Following the 80/20 rule, whereby you charge the battery only to 80% of its capacity and never let the charge fall below 20%, will make your battery last longer, but it's only possible if the battery has a charge indicator. Fortunately, many tool manufacturers now include these indicators on their batteries.   

The difficulty of the task for which you use a string trimmer can affect its service life, especially if you use a lightweight tool for a heavy-duty job. Don't expect an 18-volt battery-powered trimmer to last long if you regularly use it to clear heavy brush, a job for which a gas-powered model would be better suited. The diameter of the string is also a factor. Heavier string (for example, 0.105 inches) cuts more easily through heavy material, but it makes the trimmer engine work harder than if you use lighter 0.080 string, and that makes the battery run down faster.

Store and maintain your trimmer properly to extend its life. Just like you'd do when storing a lawn mower, always add stabilizer to the fuel or empty the fuel tank before storing the tool to prevent a clogged carburetor and a possible date with a service technician. Similarly, always remove the battery from your cordless trimmer before storing it. When it comes to maintenance, keeping your trimmer clean and free of grass clumps, re-stringing it when necessary, and doing simple tasks, like clearing the fuel filter when it clogs, should help the tool meet its life expectancy. 

It also matters what type of fuel you use with your gas trimmer. Gas should have the octane rating recommended by the manufacturer, which is usually 87 but could be higher, and contain no more than 10% ethanol. Ethanol absorbs moisture and is a common cause of carburetor clogging.