G.E. Electric range
Appliance service technicians use a pyrometer (expensive thermometer) to get an accurate idea of the oven temperature. You may be able to get a rough idea of the oven temperature using a cheap, store-bought oven thermometer but I wouldn't use one as the basis for any repairs (especially expensive ones).
** maybe replace the element **
Electric range elements usually only work or they don't. If it working (glowing red) it is not the cause of your problem.
** should I consider a new oven after ten years **
I wouldn't. Just the temperature being out is not a catastrophic failure. If you're unable to determine the cause yourself, having a trained appliance service technician would likely be worth while. I would recommend you having it checked out regardless before replacing it so you can have an accurate estimate on repairs to compare against the cost of replacement.
The Appliance Information Site
[This message has been edited by DanO (edited February 10, 2004).]