Oven Troubles....Again

I am having oven troubles....again. Seems me and ovens just don't go together. I posted back in the end of 2008 about those troubles. Well, it seems it's happening again. I was baking the other day when the oven shut off and displayed error P3. I turned the oven off and restarted it and it worked for awhile before displaying the error again. Last time we had trouble it cost $163 for the part. Now, I am wondering, do we fix it again or start shopping? Our stove is 7 years old. So, I've started popping over to Castanet and having a boo at used ovens. I am prepared to use the BBQ and toaster oven over the summer so I have a chance to research and figure out the best course of action. It seems appliances now are made to last such a short time. It used to be I thought extended warranties were a waste of money, now they almost seem like a necessity! My brother and his wife bought all new appliances for their new home and have already had several serviced, multiple times! They are thankful they got the extended warranty, let me tell you! It seems so throw away to have big appliances needing to be replaced in less than 10 years! Any thoughts?