I was thinking to get another trimmer to use as a backup. Here are my choices: STIHL fs55r or STIHL fs56r-ce. I know that that the fs55r is not commercial but, I would just use it for 2-3 days if my fs90r were to break down and also my helper would use it sometimes. As for the STIHL fs56r-ce I don't really know much about it. BTW I am also considering other STIHL models also, I am limited to STIHL, REDMAX and ECHO because that's what my dealer sells. I can only get ECHO at my local Home Depot. Thanks for all of your help!