Armed Polite Society

I think that people going into regions where they are likely to be exposed (such as people in the military) may still be given additional "boosters" for a variety of reasons including potentially mistaken records of previous vaccinations, variations in individual immune systems, and so forth.  Easier to just give the additional vaccine.

True, and I can understand that thought, especially in a military setting but generally any American going to a place where diseases that are normally "one and done vaccinations" are endemic is recommended to "update" their vaccines.

I would just say, especially in the context of this thread on not having, shall we say, 100% confidence in Public Health officials and pharma companies, that when they say "Yeah this vaccine gives you 99% protection from this rare disease you are unlikely to ever encounter for life!  Totally!" and follow that up with "Oh, you are going somewhere you might actually get exposed to the disease?  You should get a booster, just in case."  I question the lifetime protection claim.

FWIW MMR and Yellow Fever were both added to the DOD "Vaccines that need to get boosted/redone" in the mid 20teens.  I had a heck of a time convincing the local Walgreens that I really did need an MMR at 35.  I think it's mostly Measles they are worried about with that one.  Interestingly, COVID is one the DOD isn't requiring us to update.  Someone decided the disease wasn't bad enough anymore to be worth the publicity, lawsuits, and hit to retention. 

I had a metric boatload of vaccinations before making eventually cancelled excursions to Panama and the Philippines at Uncle Sam's request in 1975.  They were cancelled because of the evacuation of Saigon in April that year.  I had a bunch of the vaccines repeated, likely for reasons cordex mentioned, just before a float to Australia in Sept. 1976.  Lots of holes in my shoulders during that time.

I stand somewhat corrected.  Many vaccines require two doses to achieve lifetime protection.  Others multiple doses to continue protection.  It depends on how the vaccine is designed.  From the CDC website:

"A single dose of vaccine provides only partial protection. The number of doses needed to achieve immunity depends on whether the antigen in a vaccine is alive or not. Because they contain living bacteria or viruses, live-attenuated vaccines can provide enduring protection with only two doses. By contrast, non-live vaccines typically require at least three doses to achieve protection that fades over time and must be restored with booster doses."
The article goes on to state that some live-attenuated vaccines do provide lifetime protection with only one dose and one follow-on booster.
Research on this subject is time consuming because most everything that comes up with the googles and duckz is related to the covids.  Very little comes up unrelated.  There may be some one-and-done shots out there that just don't come up due to the overwhelming bunch of covid related stuff that results from most search terms.

I, for one, am so glad congress has solved the border crisis and the economic and budget issues facing the US so they have time to circle jerk each other for media hits.

You mean just like they do for the border and budget?