If a salesperson claims they have a panel that will last longer or produce more that 100% of the panels rated energy production, they are misleading you.
It is important that your solar company analyze your needs and care enough to present you with the best system and sizing for your family. A properly sized, priced and financed solar system should provide a good positive cash flow with no cash out of pocket for the average families situation in PG & E territory with SMUD areas usually being possible with average bills over $150 month, see #4 below.b.
A very important question is, "How many years has your company been in solar, are your installers in-house, or subcontracted, and are they paid by the job or by the hour?" A dedicated company with many years in solar is more likely to give you a truly quality installation and be there to serve you many years into the future. Companies with in-house and caring installers that are paid by the hour generally result in a much higher quality installation than slam in the job, paid by the job, installations.c.
Optimized systems allow you and the installing company to monitor the system's performance right down to the individual panel. SolarEdge Inverters with "optimizers" do this and are a popular choice. "Micro-Inverters such as Chilicon and Enphase do this as individual inverters under each panel and therefore do not require a main inverter by your main electric panel. String inverters are not recommended because the "string" only works as well as the worst performing panel in the string and there is no way to know of a panel is not working at its best.d.
Oversized systems, meaning systems larger than you need for the best return on your investment, make the salesperson more money because it is a larger system. Unfortunately, some solar salespeople and companies are only interested in putting the maximum amount of panels on your roof as possible