I use starch in my quilting. I use the liquid sta-flo and mix to a 50/50 ratio. I apply the starch after I have pre-washed my fabrics during the ironing process. I may apply again after folding selvage to selvage as well to get as sharp a crease as possible to help make my cutting more accurate. Rarely do I apply more during the piecing process.
I do wash my quilts after they are finished and before gifting so any residual starch is then gone.
While my fabric is not 'board stiff' it does have a reasonable stiffness to it - probably less than if used prior to pre-washing - and I do find that it helps stabilize the fabric during both the cutting and sewing process.