There's always someone at the beginning 9.30 and the end 6.00
The mail also comes from Raleigh. If the mail is sorted late in Raleigh there could be a delay in Durham along with traffic. Once the mail gets to the post office in Durham the carriers still have to sort the mail for their perspective route so it can be a lot of reasons to factor in why you may receive your mail late.
Many reasons... for one, being a mail carrier is a difficult job... a lot of times they are understaffed. When a carrier calls out of work, their route sometimes get forced on another carrier in conjunction with their own route thus making mail late.
Thanks! Your answer is awaiting moderation.