Motor Type
Brushless motors are the more durable, efficient option and are increasingly standard on mid-range and premium trimmers, including the EGO ST1521S.
Brushed motors rema in common on budget models like the Greenworks 40V and keep the price down for occasional, light use.
Line Feed System
How a trimmer feeds new line matters more than most buyers expect until they've dealt with a jammed or tangled bump-feed head mid-job.
Auto-feed systems reduce that friction, and premium systems like POWERLOAD remove it almost entirely.
Battery Ecosystem
For cordless trimmers, the battery platform is effectively a long-term commitment.
EGO's 56V ARC Lithium, Greenworks' and Ryobi's 40V systems, and Worx's PowerShare platform are all distinct ecosystems that don't cross-compatible with each other.
Choosing a platform you're likely to expand into other tools pays off over time.
Shaft Design and Attachments
Straight, adjustable shafts generally offer the best combination of reach and attachment compatibility.
If attachments like a brush cutter blade or pole saw head are a possibility down the line, confirm the trimmer supports a click-on or compatible attachment system before buying.
Our picks
Products we recommend
As an Amazon Associate I earn from qualifying purchases. Picks are based on manufacturer specs, independent reviews and owner reports.
EGO
Carbon fiber shaft keeps weight low without sacrificing reach on an incline
- 15-inch cutting swath
- Carbon fiber split shaft, adjustable length
- 56V ARC Lithium battery, 2.5Ah included
- Brushless motor
- Under 8 pounds
✓ Pros
- Carbon fiber shaft keeps weight low without sacrificing reach on an incline
- Adjustable shaft length helps you stand on flatter ground and reach up a slope
- 56V torque holds cutting speed even when working at an awkward uphill angle
✕ Cons
- Still needs two hands for full control, no single-handed operation on the steepest grades
- 56V battery adds cost over more basic 40V options
- No specific anti-slip grip texture beyond the standard handle
Worx
Lightest trimmer in this list, easiest to hold steady on a steep, short section
- 13-inch dual-exit cutting head
- 40V PowerShare, 2 x 2.0Ah batteries included
- Under 5 pounds
- Pivoting head
✓ Pros
- Lightest trimmer in this list, easiest to hold steady on a steep, short section
- Two batteries mean you're not stuck mid-slope with a dead pack
- Low weight reduces arm fatigue holding the tool at an uphill angle
✕ Cons
- 13-inch swath means more back-and-forth passes on a wide slope
- Fixed shaft length, less reach flexibility than the EGO's adjustable design
- Less motor torque for thick growth that often collects on untended slopes
Husqvarna
No battery to run down partway through a large sloped lot
- 28cc 2-cycle gas engine
- 17-inch cutting swath
- Straight shaft
- Smart Start recoil system
✓ Pros
- No battery to run down partway through a large sloped lot
- 17-inch swath covers more ground per pass on long hillside runs
- Straight shaft gives good reach on a graded slope
✕ Cons
- Heavier than any cordless option here, a real factor on unstable footing
- Vibration and engine weight add fatigue over a long uphill session
- No adjustable shaft length to change reach on the fly
FAQ
Common questions
What's the real difference between a brushed and brushless motor?
A brushed motor uses physical carbon brushes that wear down over time and create friction, generating heat and reducing efficiency. A brushless motor uses electronic switching instead, which runs cooler, lasts longer, and draws less battery for the same output. Brushless motors, like the one in the EGO ST1521S, generally cost more but hold up better under regular use.
What line diameter should I buy?
0.065 to 0.080 inch line handles typical lawn grass and light weeds. 0.095 inch or thicker is better for dense weeds and woody stems, provided your trimmer's head is rated for it. Using line thicker than your trimmer is designed for can stra in the motor and reduce line feed reliability.
Do I need a trimmer with attachment capability?
Only if you're likely to add an edger, pole saw, or brush cutter down the line. Attachment-capable trimmers, common on gas models like the Husqvarna 128LD, cost a bit more upfront but can replace buying separate standalone tools later.
How long should a string trimmer last?
A well-maintained battery trimmer from a reputable brand typically lasts 5 to 8 years of regular residential use, with the battery often needing replacement before the motor does. A well-maintained gas trimmer can last 8 to 10 years or more with regular carburetor and air filter service, though gas engines require more consistent upkeep to reach that lifespan.
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