Thanks everyone.
I used to pin all the time. Lately, however, when sewing 2 squares or a square on the end of a rectangle etc. I have just been lining the two up and run them through the machine without any pins. This is when I'm noticing the different lengths after piecing. I assume that when I pinned they were fine 'cause I've only noticed this recently when I stopped pinning.
Polly, I've also had problems with some of the misc. fabrics I've inherited. They are different fibers, weights, finishes etc. I've just learned that it is apart of it with them, but pinning and the walking foot greatly reduce it, and my projects with them are not meant to be perfect. The ones I've had issues with lately are quilting cottons and seem to be the same weight.
Nope, not cinched down on the pressure Kay. Don't think I can adjust it myself (bernina 145). I do as you suggested on the longer pieces, but these are smaller squares, that are causing the current problems.
I'll try butting them up against the needle to start Lisa. I have done this occasionally if my machine was already set to stop with it down (not often), but don't know if I had problems then or not. I'll be more observant and see how it does.
I guess if that doesn't work I'll have to go back to pinning like John, Polly and Marcella suggested (sorry Lisa that sounds like less hassle to me than starching but thanks for the suggestion) or work with my walking foot to get better acquainted with it and get my seams accurate. I does have a mark on it but it is in an odd spot (at least to me) to try to watch and keep the edge lined up. Perhaps I'll have to decide on a different needle position and make my own 1/4 mark.
I guess I need to stop trying to speed up the process. Again thanks everyone for the advise.