I know of some who like to have the romex pulled tight between staples, around corners, and even on home runs in the attic. And have it tight all the way into the box. They run the staple down enough that it won't pull through when the cable is "pulled tight".
I like the staple to make "light" contact, so that the cable is secure, and then sweep it generously at corners etc. My premis is that the conductors will be expanding and contracting from seasonal temp. changes, especially in the attic. Also from some heating at heavy loads. It needs to move. If it's pulled and stapled tight it will someday rub through the cover and short, possibly start a fire.
Am I overboard here? So many guys pull tight that it appears to be ok. Are there any instructions in print by the manufacturers?