I went home in July with a Vista notebook, and returned yesterday (same apartment) with a Win8 notebook. Plugged in to the old router and everything including internet was up immediately without skipping a beat. I had really thought I'd have to find my old router password or even reinstall everything. Thankfully no sweat this time.
Protip: Don't wake up in a hotel with sketchy wifi, and assume there is a problem with your machine as opposed to the crappy hotel wifi. In my defense, it was Early In The Morning. But I went to the settings and tried various fixes to no avail. I then saw something that said "refresh settings" but didn't read it carefully enough, assuming it's akin to refreshing a web page. It's not. It basically saves your files (not programs!) and reinstalls Windows 8, including all the bloatware you thought you got rid of already. The downloaded install files were still there I found out, thankfully, otherwise it would have been much more of a time-waster/hassle than it was.