A home builder, as a standard procedure, includes a one year all-inclusive warranty, on virtually everything operating satisfactorily, new out of the box.
How is trust established? This comes down to past performance. Do people who have older homes still have contact with the builder? Keep in mind – no builder typically extends the individual equipment warranties offered by the manufacturer. Those often depend on your use patterns, your maintenance and finally your unique climatic factors.
Will this builder at least help you find service and or parts?
An extended warranty program, unless purchased with policy enhancements will not cover these failures.
At this point, self-insurance might be best. Remember, the State of Oregon requires the builder to provide a 10 year structural only warranty.