Good question, Pamela! Yes, it will take more than one old sweater to make a rug. Conveniently, I am in the middle of a wardrobe purge. I have a basket full of well-worn items. Also, single event items - t-shirts from the blood bank, Breast cancer walk, Huey Lewis concert, 25th high school reunion (next year: 40 years!) - and stuff I just no longer like.
I am cutting out the sentimental bits and saving them for a future quilt.
The rest goes to throw rugs. I've been experimenting with color for different rooms, and am keeping track of how many sweaters/shirts I'm using.
12.5 x 12.5 inches = 6 t-shirts
8.5 x 9 inches = 2 t-shirts, .75 turtleneck
How big a rug will this pile of red make?
Time will tell.
The process is a bit unwieldy and must be done in small spurts. My shoulders, arms, and hands are getting a real workout. I have acupuncturist-prescribed stretches for the painful left thumb, am "liberating" my shoulders through several yoga postures, and yes, Pamela, I'm throwing, but with the right hand. It's all I can do to just hold these fat needles with my left hand.

