If you're using a Ryobi cordless battery string trimmer ($99 at Home Depot), you eventually need to learn how to restring the weed eater to add more cutting line after it wears away. You can ...

Most are dedicated string trimmers, but Ryobi also makes a couple of 2-in1 string trimmers/edgers, a trimmer/brush cutter, and it also has weed wacker attachments for its Expand-It system.