I was born way before you and used to wear a lot of that ugly polyester....ok, don't go there, it was the style! I sewed most that I wore. I would end up breaking the ball needle before it ever got to not going through the poly. I'm sure it shredded thread and I'd change it for sure, but I remember them lasting a lot longer than my sharps do. I don't break as many now, but every once in awhile I forget to let the machine pull the fabric and I'll pop one.
Give those girls a hug from and Aunt Sharon and tell them to give you two each. Hugs