i wash the fabric how ever i think the finished product is going to be washed (if i know) always warm or hot. and then i throw it in a hot dryer, so any shrinkage is going to happen before i start sewing. flannels keep shrinking for numerous washes but i only pre-wash once. and if a fabric is bleeding i will wash it a second time but no more...if it still runs after the second wash it is used in a way it's not going to matter but i do not waste anymore time than 2 washes on it.