The only complaint that I have is, mine doesn't have a timer to shut the unit off. You have to set an alarm and make sure you watch it.
Usually every 10 to 15 minutes I take it out and wipe it down, put back in and turn it it to a different area
Dave,
Since you set the temp (very accurate) to the safe temp for that brand, leave it in for an hour and then check it. If there's oil, wipe it off. If there isn't, then you're done.
I wouldn't bother to check it every 15 minutes, unless you happen to be very close by.
Of course, timers that go to wall sockets are cheap. I use one for growing seedlings inside the house in the spring.