I use muslin all the time, it holds up very well, although really I've only been quilting since 97'... I guess it would depend on the 'weight' of the muslin. I like a heavier weave ..

I was buying muslin at a Hancock Fabric store one day and they lady asked me what I was using it for. She said to be sure and wash it first as certain muslins shrink a lot. I went with the more expensive and haven't had a problem.

I've been quilting for over 30 years using muslin and sheets occasionally for the lining - both have lasted very well, no sign of wear.
I have also used both blankets and old fraying quilts as batts - they both work well.

I have used old blankets a lot of times for batting. I have even used new blankets because they are often cheaper than batting. Yard sales are a good place to find them.

Quilters in the old days used muslin for backing. My husband's grandmother made several quilts, the tops are now mostly faded and the appliques are falling apart, but the muslin background and backing are still in very good condition.

I am still fairly new at quilting, but I prefer muslin. just get a good quality. I love the feel of it.

I have a much used and loved 21 year old quilt with a muslin backing that has held up very well though 2 kids and many washings. I used good quality muslin however. Well worth the extra few dollars.

Muslin is pretty tough stuff -I"ve used blankets for quilts My family are campers- NO AIR MATTRESSES-so blankets add a lot of padding for our old bones and about 9 yrs ago my one brother who is 6ft 4 and weighs in at apprx 375 [this is his -tiny-wgt] I re-made his hammock I made him a scrappy plaid top with a blanket center and muslin back and he's still using it.The thing with muslin is it shrinks I wash and dry it a couple times before using it.

Muslin is fine. I get it at JoAnn's and it holds up very well on all that I've used. The top wears out before the back for me.

I made a QAYG quilt once with muslin backing. This was before QAYG became popular. I needed to have a project to work on as I was traveling with my OTR husband. That was back in 2000, and has been washed many, many times. The muslin is still holding up like new, but some of the front pieces are worn out.