To GG1968:
If I understand your question, the Nest Learning model does have almost the equivalent of what a regular not-smart thermostat calls a Permanent Hold. It's Eco Temperature. If you set your Eco temperature to 62, and turn on Eco mode, then the Nest will tell your heating system to heat to 62, all the time. (That's if you're running heat, but it's the same principle if you're cooling. I don't know how Eco temperature(s) work if you're asking the Nest to switch automatically between heating and cooling to maintain the same temperature at all times.) It's only "almost" equivalent because your Eco temperatures for heating are restricted to the range of 40 to 70, at least on our model. If you want to hold at 72, for example, you do have to reprogram the Nest manually as davidking writes.
