I consider myself to be one of the few users here who has a mass of programs installed and intricately configured and well organised yet it would never take me more than a night to reinstall them all and configure it back to how it was prior to clean installing.
I used logic in this regard by backing up key program config files and directories to a 2nd disk and synctoy those backups weekly so that when a reinstall is done I just install the apps and copy the directories over thus all my customisations and settings are restored instantly for all applications.
If it's taking you 3 days then there's an area of your daily computing you need to advance!
Not sure if you read my post correctly or not? However, you will notice that I said I use Acronis TI for making full images and I carry out backup tasks obsessively. In fact with TI one can now mount that image as a virtual drive and move ones files apps data etc. onto the new system. However, that is the easy bit. One still has to install the programmes again and then configure them. Just reinstalling MS Office and downloading all the updates plus setting up all my various email accounts takes hours in itself so unless your nights are longer than mine I'm not sure how you achieve such a feat. When I said three days what I really meant was three evenings after coming home from the office