Differences noticed between garment sewing (with woven fabrics) and piecing
 

I learned to sew garments when I was young(er!) Way back then, I learned using woven fabrics.

So - some of the things that took some adapting to when piecing quilt blocks -

* that 1/4 inch seam allowance! Why do (woven) garment patterns have a 5/8 inch seam allowance?

* for piecing, the thread does not need to match "exactly" - I have also learned that it does not need to match "exactly" for inside garment seams, either.

Those are the two things that I can think of at the moment -

Do you have "habits/customs" that you've had to rethink?

I remember during my first quilting class I automatically pressed the seams apart from the inside.

Garments have 5/8" seam allowance because we put pressure on the seams when we move, and a smaller seam allowance would be more likely to ravel and come undone. Quilts have the smaller seam allowance because there is not the same pressure on the seam, and a larger seam allowance would make the seams bulkier and the quilt heavier.

Grain is very important when sewing garments, but not as important with patchwork.

And the big one - a sewn garment may or may not fit me when it's done. Quilts always fit!

I still think grain is important when piecing.

The garment fitting part - I was soooooo dumb - I thought if I kept buying different patterns, I would eventually find one that would fit without doing any alterations. (Although some did fit better than others.)

I think that is the main reason I abandoned garment sewing and went to bags and quilts.

I used to make all my clothes and some for my son when he was small. But i hated altering so luckily I never had to. Recently my son's ex MIL asked me if I could alter a dress and I told her no. never did and would hate to mess it up.

With quilts grain isn't important to me. I use to make clothing, no desire to return. Quilts need no alterations and always fit. A lot more fun to make too.

Making clothing gives you a one of a kind wardrobe. Then you outgrow those beautiful clothes and have to start again. I can keep making new quilts but keep the older ones to be used again. They still fit!!!!

I seem to remember reading that many years ago, there were different recommended seam allowances for different kinds of seams, and they were all averaged to 5/8" to make it easier.

I quit making my own clothes when I found out how inexpensive thrift stores were. That, and patterns went up in price.

When sewing garments and using the 5/8" seam allowance, I try the item on and if it fits I'll zigzag or use and overcast stitch to finished the seams close to the original stitching line and then trim to 1/4". The larger seam give me too to make adjustments if I have to.

I had an extremely hard time in quilting class learning the ‘scant’ 1/4 seam, it was almost impossible. Then I thought we wasted so much thread. Yesterday while doing some long arm work, I threw thread away, I wonder how much it cost?

I never made many clothes but sometimes I made shorts for my boys when they were little. I appliqued cute things on them. But I really only like making quilts and the like.
I agree with you, Bear, that grain is important for quilting too.
I've noticed that some clothes made these days aren't always on the grain. I don't know if it's on purpose or not. I have some slub tees from J.Jill that aren't but they are very comfortable.