Timers on espresso machines
A big prosumer or commercial espresso machine takes between 30 minutes to 90 minutes to reach equilibrium where it is truly ready to go, much longer than just the time it takes to heat up the boiler because the huge mass of metal has to be heated up, too.
Source: http://www.roaste.com/CoffeeBlogs/wakeknot/Timers-espresso-machines