As others have said - figure out what you prefer, and work that way. I always press my seams, because I think the end result is better when I do. I also prewash everything (esp. since a disaster involved a blue & white quilt). Ironing that pile of fabric out of the washer is *not* my favourite activity, but it is an absolute necessity. After that, I only press before cutting if the fabric has a fold in it (ie, cutting when I folded the fabric to store it).