HobbyLock 786 Serging .... A serging question.....

My bestie from 2nd grade gave me her serger, when she upgraded!  How cool is that.....but it has taken me *ahem* many years to finally get it on the table and use it.

Sew, I'm making Aggie Mom scarves for our boutique.  We use the profits to fund scholarships.

Here's a couple of pics....

Question: Sew, if you sew strips of fabric together using the serger, then finish off the edges with serger, do you have to go back and fray back each strip that you've sewn?  Or just fray back where there are existing thread tails.

My serger experience is limited!  Y'all let me know in the comments or a phone call!

Thanks!