As to things that can fail on an old range - ignitors ( top and oven) convection fan motor, hinges, thermostat, and electronics - like the main control board. I think you might want to contact a local authorized Viking repair person to get an idea about the potential costs involved for refurbishment and maintenance, and to confirm parts availability. I have a Viking and the hinges have failed and they don't offer replacements anymore.

Consumer Reports gives the average life expectancy of a gas range at 15 years. So consider that the range has met it's maximum life in any decision to continue with parts replacements.

It doesn't matter how much you paid for a range as all of them are made up with most functional parts that are common throughout the industry.

Here is a link that might be useful: Appliance Life Expectancies

Thanks Barryv and jakvis. I appreciate yur input.