About posting service in Nepal I have heard many stories. And read probably even more of them.
The thing is, I don´t really know how it works. Apart from its basic task as delivering or sending emails, it is hard to go into the details. Why? Because there are actually no street names or exact addresses. There are post boxes and I know that some people use them but with all the population in Kathmandu I don´t believe that everyone has his own postbox. And during my over two months stay there I didn´t see a single postman. Nowhere. Maybe because of the street dogs, and as you already know the street dogs are everywhere, but I still think it´s a cliché.
If you want to send a parcel or postcard though there is another thing you should have in mind. There are few post offices in the city and they are not really marked as such. Sometimes you can send the postcard from the bookstore, because they offer it. Alex sent it like that but I´ve read on the internet that sometimes they don´t, as well as people open letter boxes, peel away the stamps and sell them again. Even at the post office you have to wait until they put the stamp on the postage stamp (or in other words cancel the stamp) and then the possibility of sending your post gets higher.
I had 22 postcards and about 8 parcels to send, so I went to the post office, because I wanted to be sure that all my post will get delivered on time. And 22 postcards and 2 parcels took the post guy the whole one hour, I think it was his first time he had such a big task to do (and I was the only customer there). So the 6 last parcels I´ve sent the other day. I just didn´t have neither time nor patience. How long does the post go? It depends on the country. My postcards to Ireland were going about 2 weeks, to Poland between 3 and 5 weeks and to Czech Republic between 4 and 6 weeks. In other words, enjoy waiting.