I personally have never left my hive wax heater on intentionally. Accidentally a few times over the years , but I have been lucky . The risk of thermostatic failure could cause a fire and then that would be unthinkable.
I would not recommend a timer to have it come on before you start work just in case it also fails. That's just me, I know a firefighter and heard so many stories, so I am very wary.
Look after your interests and don't risk it are my feelings on the situation. Take care .
