Default [Q] The correct order of root

Hi,

I want to root my xperia z1 compact.
As i read, there are few steps that i need to take before rooting my device - backup TA partition, installing CWM, rooting the device.
Both of the CWM/TA backup require that the device will be rooted but if i will root my device without backing up the TA partition i cant go
back and reinstall the stock rom.

What is the correct order of the rooting process?
If the rooting process will get done correctly can i reinstall my stock rom back(for warranty issues)?
What are the downside for rooting - i want it mainly for Titanium backup and the Lba apps?

Thanks for any help!