Regular mail literally comes sorted and the first 2 hours of every morning is spent standing in front of large desks with walls with slots of every house on your route where you sort the mail manually and combine it with all the bulk/mass mailers.
It's not like it's a random bag full of mail and mailman is just reaching in and delivering whatever they pull out. It's all ordered by the path they take on the route. The route is mapped out by officials and they have to scan 4-6 barcodes on every route or their supervisor literally has to go out and get the scan or they cannot go home that night.
Regular mail literally comes sorted and the first 2 hours of every morning is spent standing in front of large desks with walls with slots of every house on your route where you sort the mail manually and combine it with all the bulk/mass mailers.
It's not like it's a random bag full of mail and mailman is just reaching in and delivering whatever they pull out. It's all ordered by the path they take on the route. The route is mapped out by officials and they have to scan 4-6 barcodes on every route or their supervisor literally has to go out and get the scan or they cannot go home that night.