How to properly load the line into a trimmer spool without long struggles. In fact, replacing the line in a trimmer is not a big deal. Whether it's a gas or electric trimmer, the spools are the same in terms of attachment and operation, so knowing how to properly wind the line on one spool will make it easy to do the same with others. To load the line into the trimmer head, you need to remove it from the trimmer. Carefully open the cover to avoid losing the spring. Take out the spool on which the mowing line is wound and properly measure and wind the new line. The only other thing is to correctly select the line diameter for your trimmer, otherwise, it may not be possible to load the line into the trimmer spool, especially concerning larger diameters.