The tracking of course depends on the package actually getting scanned.
I had an item I bought that somehow missed scanning for nearly its entire trip through USPS. Tracking showed the label as having been printed, then.....Nothing. And nothing showed for a couple weeks. I asked the seller if it had actually shipped since I've had stuff get missed at the bottom of a box or under something else on the desk.
USPS didn't help by changing the expected delivery date to whatever the date would be the next day. (Neat way to be 99.9% on time, simply adjust the expected delivery date
)
Then one day it was scanned as "out for delivery" and arrived with that days mail.
Steve B