Pilling is caused by abrasion of threads that have low twist. It cannot be remedied if the fabric is constructed of low twist yarns. Double sided flannel has more fiber per inch, more compact, and less likely to be subjected to abrasion in the washer or dryer. I prefer to always wash flannel in warm to hot water and dry in the dryer to get the shrinkage out. It generally shrinks more that regular cotton fabric. I go by fabric name and use those I have had good luck with like Moda, Maywood and Timeless Treasures. I have had night gowns that lasted for years without pilling-snuggly and nice.