Update: We didn't get the upgraded panel. Thanks for everyone's advice!
Ted and I need some advice in a hurry: The electrician is about to install our electrical panel, and we need to decide whether to pay an extra $2,350 for a panel that's compatible with a backup generator.
We have no immediate plans to install a backup generator, and we hope the grid stays reliable enough that we wouldn't need one. But if we do want a generator one day, it would be a lot cheaper if our panel is ready for it.
Note that our house is run entirely on electricity. No wood stove, no gas range. Our water comes from a well, which requires a pump, and our sewer hookup requires a pump as well.
The idea of burning propane to power our house gives me the willies, but if there's an extended power failure I'd rather burn propane than abandon ship altogether.
[I should add that the solar panels won't work in the event of a power failure. There's an automatic shutoff if the grid supply goes down, in order to protect line-workers.]
Basement rim joist areas; holes cut for plumbing traps under tubs and showers; cracks between finish flooring and baseboards; utility chases that hide pipes or ducts; plumbing vent pipe penetrations; kitchen soffits above wall cabinets; fireplace surrounds; recessed can light penetrations; poorly weatherstripped attic access hatches; and cracks between partition top plates and drywall.