I hear so much about which kind of thread to use... I have been using 100% cotton for my 100% cotton material piecing. Then I 'hear' the cotton covered polyester is better for longevity... and regular thread for quilting - I use 100% hand quilting cotton for quilting... I want my quilts to last for - well, forever - so what advice to you all have? ALSO, what is the difference between heirloom quality quilting and just quilting?