Your installation or update is rather slow
You did not configure the best debian mirror for your network
The list of debian mirrors can be found on the debian homepage.
Paste the above link your web broser and you will find the mirror servers. With netselect you and select the "best" mirror for your location on the internet.
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.