Normally, the worm-up of tube amp to the tube's specified operation parameters is much faster than for transistors. Tubes to some degree don't need to reach certain temperature of operation since they're not depended as much on the temperature as transistors but unlike transistors, they need to be mandatory wormed up before passing an input signal to avoid its short life.
If you plan to stay home and listen to the music, than keep it on. Turn off when you go to sleep or out of home. It'll save tube life and electric bills. If you give 20...30 min of worm-up before passing an input signal, it can be considered as normal for tubes. Non sufficient worm-up time may result on large difference in tube's operation characteristics that maybe distructive and shortening the tube life.