When did we Forget How To String a String Trimmer - use one string only.

This one was a little baffling. I've done it wrong forever as many of us have. Many people cut 2 strings and spool them together. The trimmer cartridge was designed to do it with one string. There's also a feature to keep the string from ejecting while you load the cartridge into the trimmer. Mine is electric but gas trimmers can be the same way.