I did mine on Monday night….(did a Factory reset on Kitkat as phone is almost 2 years old and starting to get a bit cludgy).
The things I forgot
Wi-Fi locations set-up (not sure if you can back these up though
Saved dictionary own words – but it seems to have kept them anyway
Bluetooth pairing – only one device and took seconds to reconnect
I did a ‘back up and restore’ – my phone has the program installed on it (not sure if it’s a Sony app or generally available), but decided not to use it in the end as I wasn’t sure how much it was going to drag back.
I thought I could select what I wanted to restore – e.g. tick the box to restore text messages, tick the box to restore app data etc. but I think it just dumps everything back on that was saved.
Contacts should be backed up on Google and take about 2 button clicks to get back.
There’s a few people who’s Facebook contact hasn’t linked up with the Google contact, but no big deal.