I did that on Monday with an applique block. Good thing. I didn't like the stitch I started using, didn't like the color I started using, had to order some new thread and tried out several stitches before I decided which one I would use. Also decided I needed to make the block bigger to start with even though I will end up with the same size. I made several changes because of the ideas I got from the applique thread that is going.

I usually cut out enough piecews to do a block so I can see how it will actueally look with the colors I've chosen. If I like it, I continue to mark and cut!

I usually do! But I've now learned that I should do this from scraps or maybe, 'ugly' fabric - so if I haven't purchased enough extra fabric for a test block, I'm not working out the kinks on the fabric for the quilt! Especially when I'm making a quilt from Fat Quarters!

I don't intentionally make a test block, but sometimes the first block or two doesn't pass muster, so it becomes a test block. Our guild made a quilted van cover from all our "test" blocks. http://www.quiltingboard.com/picture...rs-t22705.html

I have never done this, but everything I read recommends doing this. I'm thinking maybe I will from now on since I am beginning to machine piece. Everything prior has been hand-pieced, so much more time consuming.

i do only when i am trying something really new such as paper piecing a new pattern or a block i am recreating without pattern measurements or a pattern, only a picture to guide me.

I haven't so far but you have a great idea. I,m going to start.

Occasionally the directions are unclear - or just plain wrong. I'd rather mess up scraps than the real thing.

But then there is "what to do with all those stray blocks"?

Twice I did and both times I needed them! In fact I just finished repairing a hole in my GS's quilt with a block I'd pieced, layered and quilted! Can't tell the difference. Forget what happened with the other, but I was equally as happy.

Only if it is a complicated block with a design that Ive never tried before.
Most blocks are simple to do with methods already done before like flying geese and HST etc.