For me, Amazon’s decision to ship USPS has broken our relationship. USPS doesn’t deliver to my house. For me here, they have window hours to pick up shipments during work hours. And I am not going to the PO to pick up a bulky items. If I wanted to do that, Walmart here I come.
I now use Chewy for pet supplies.
And I use Walmart more.
That’s the thing. Each carrier has their own limitations of what they can and can’t service. USPS does deliver to my house every day, except for Sundays, which they have added for package delivery only. Neither UPS nor FedEx delivers to my house on Saturday or Sunday.