Do you wash your fabric BEFORE you piece? Does it make it easier to piece the pattern if you wash the fabric first?

I always wash mine before if I am hand piecing. It definately makes it easier to needle. I don't always if I am using the machine unless I think that the colours are likely to bleed. But you can always use colours to help with this.

I do not hand piece but I do hand quilt. Opinions on prewashing are as varied as the people on this board. I am in the prewash camp for all fabric that comes in my door (disclaimer: I do not buy precuts which should not be prewashed, such as jelly rolls, honey buns, charm packs, etc)

I prewash to:
Remove commercial sizings and chemicals applied to fabs.
Preshrink
wash out any excess dye or to set unset dyes using Retayne in an effort to eliminate any issues with bleed.
I feel prewashing is just a good pre-emptive step no matter what you are doing with the fabric

I also prewash all my fabrics, the reasons are the same like the ones Feline mentioned. Furthermore I prefer to hand quilt prewashed fabrics because for me they are softer and easier to needle.

Thanks for that advice. My hands get so dry when I'm hand piecing (I haven't been pre-washing my fabric). I'm thinking now that the chemical in the fabric may be making my hands and cuticles so dry.

Ditto!

i do most of the time pre=wash...does not matter if i am hand or machine piecing. pre-washing removes the sizing and any other chemicals from the fabric and can make stitching easier.
a good sharp-new needle is a good idea too

Just to let everyone know, alot of companies have chemical agents that are harmful to skin after constant contact. They use these chemicals so while shipping to other places bugs and rodents do not harm them. I use charm packs and jelly rolls all the time, but I prewash them in the sink with detergent and lay them all out on a large terry cloth towel to dry.