Cordless yard trimmers have an immediate advantage in that they are so easy to move around the yard. Being cordless means they are not tethered to an extension cord and have no limitations as far as where they can go. With an electric corded yard trimmer you are limited to the length of the extension cord.

Cordless trimmers will use rechargeable batteries (not counting the gas powered yard trimmers). You should expect to get around 30 minutes of use before you will need to change the batteries. With a pair of batteries you should be able to trim all but the largest yards before both batteries are drained of power.

How long until a cordless yard trimmer runs out of power: around 30 minutes per battery. We should mention that as the battery runs down the trimmer will be progressively weaker.