tl;dr: YOU HAVE ONE WEEK BEFORE STUFF STARTS HITTING THE DANGER ZONE.
First-Class Mail® Service Dec. 20
Priority Mail® Service Dec. 21
Priority Mail Express® Service2,Dec. 23
USPS Retail Ground® Dec. 14
Do we offer other shipping services? Heck yes we do! But almost no one ever picks them. It's safe to assume that they fit a reasonably similar profile.
You know what DOESN'T take shipping?
So if you want to get your loot to the intended destination (your booty or someone else's), pay attentions to the ships above!