If the quilts are not too large, you could also look at the invisible or international stitch, as shown here. It goes pretty quickly—a crib quilt took about 2 hours.
https://www.youtube.com/watch?v=cEkHht2oJsg
Or “big stitch” quilting. I used this one a quilt 10-15 years ago, and it is fine. Used perle cotton.
http://blog.sulky.com/big-stitch-qui...cotton-thread/
But to your question: if done with perle cotton, hand tying can last about forever. Yarn, don’t know.