We renewed our passports last year and they are good for another 10 years. That ought to be more than enough for this trip.
However, a couple of weeks before leaving, I discovered that the State Department allows for a second passport, limited to two years.
The value for us is that:
1. We have back-up passports in case we lose one.
2. Some countries are picky about where you have been. Israel is an example of a country others don’t like.
3. Should we need to present a passport for a visa and return later to pick it up or have it mailed to us.
I set appointments with the embassy in San Jose and confirmed via email what they needed and that they could process the application. They responded and also said we could pick them up in 7-10 days and that they would hold them for up to three months.
Update: We picked them up May 23 and they are good for two years! We did have to remind them not to void our other passports.