Our old oven was completely nonfunctional after more than 20 years.  We bought our new oven and after reading the manual we were able to use all of its functionality.  Only one thing was not clear from the manual.  When you set up a timed cooking cycle, it was not clear that the warmup was included in the time interval.  Depending on temperature, the warmup can take up to 15 minutes.  If you have a short time set up, then the food can be undercooked. One other thing.  The oven vents into the room as there is no provision for external venting.  This can be a nuisance when running the first use of the oven because very noxious fumes are vented into the room which requires that you open all of the windows and doors.