If you want it smooth you have to shave every day. In my case the smooth dome can last maybe 10 hours in winter when it's cold, 6 to 8 hours in summer with the heat and sweating.
I have shaved in the evenings a few times and I stay baby butt smooth until well into the next morning, maybe 12-14hours. Once you get up and start your daily routine the stubble won't take long to appear