Head Type
This feature typically comes with two options. A fixed head is the basic, and often the cheapest grass trimmer you can buy. The other version is a pivot / tilt head. This is beneficial as it allows you to create a neat cut, down the side of your grass. Other grass trimmers take this a step further, allowing the grass trimmer to lie flat, then letting you cut underneath bushes, trampolines.
Cutting Width
In basic terms, the larger the cutting width, the more grass you will cut at a time. While this will do the job quicker, it may not be the best option. If you have a garden with lots of delicate flower beds to cut around, a smaller cutting width is best, to avoid damaging your plants.
Single or Dual Line
A dual line will have two cords that will cut the grass, while a single line will only have one. An additional line will cut the grass quicker and is most suitable for thicker, longer grass.
Line Diameter
If you have thick grass, a thicker line is recommended. Thinner lines may struggle to cut the grass and take longer. If the grass is maintained and cut regularly, a thinner line is more than suitable.
Spool Feed
A spool is where the cutting line is stored and comes with two options. You can buy a grass trimmer that feeds the line automatically or one that you have to pull manually. Manual feed machines tend to be the cheapest grass trimmers.
Comfort
If you’re tall then you will want to make sure that you buy a grass trimmer with a telescopic shaft. This allows you to adjust the height preventing you from having to bend over when cutting the grass.
Plant Guard
Most good grass trimmers come with a plant guard which protects your flowers and trees if you get too close to them whilst cutting the grass.