I prefered to just rent the biggest Sprinter, throw everything in there and get it over with in one go.
Packing everything up at my old flat: 2-3 days
Loading & unloading the van, including the drive to the new flat: 1 day
Unpacking and setting everything up: 2 days (with the help of one other person).
Paperwork for leaving one country and entering another country (like for instance a permit to actually stay here), getting a new bank account, getting registered everywhere, cancelling almost every insurance, getting proper number plates for my car, getting new insurance, a new drivers license, giving proof of insurance to half a dozen people, and a lot more bullshit I can't even remember: more than a month. Actually physically moving my stuff from A to B was like the easiest part of all this. The paperwork in the other hand, especially with the clueless German offices... oh dear.
I'm not exactly keen on moving, but as long as it's within a country's borders, I don't see it as such a big deal, because a lot of stuff simply stays the same (insurance, bank account and so on). You don't have to get permits for everything and you don't have to cancel virtually every insurance and financial commitment you had so far, while getting set up in a very short amount of time in a new country where you start from zero, so everybody looks at you a bit funny because the bank doesn't know if they can trust me, the insurance company wanted to know my *complete* medical history since birth, I had to get a new driver's license, I had to re-register my car (including a number of tests), I had to get all my stuff through customs (which means I had to have a very precise list of all the stuff I was bringing into the country), and so on... so every time somebody complains about physically having to move stuff from A to B I'm like "dude, that's nothing...".