Even people who don’t write letters anymore are in the post office this time of year. Leaving the questions about overall viability and possible service cuts to Congress, Springfield-based U.S. Postal Service spokeswoman Sue Litterly says, “Our job is to give universal service, and that’s what we do. We’ve evolved in a different way because the quantity of First Class mail has diminished so much, but we are the delivery people of choice for package business. We are!” Litterly says the deadline for sending mail in time for Christmas is December 20th for First Class mail and December 21st for Priority Mail.