It's all the time.I think the main mistake people make is gripping the stick too hard when they play on pillows. Or anytime, period.
They key to everything is relaxing. This includes the hands too. When I'm relaxed I can play faster, for longer periods of time.
Doing a 30-40 second stretch of blast beats is easy at 230bpm+ when I have been practicing hard for a few weeks because I am relaxed. If I decide to skip practicing, don't do any pad work, and just wing it after a few weeks my arms, hands, shoulders, back, will tense up when I muscle it out and it either sounds bad or falls apart.
You can HEAR a relaxed drummer compared to someone gripping those sticks.