H1b past 6 years and GC process

[cmsdelhi]

On H1b Since April 2012.

Changed employers twice and as a result my current H1b is valid until September 2020. (I have an approved I140).

Current employer suggest they will start the process in January 2019.

Considering it will take around 8 months for PERM and 6 months for I140, I might have both approved around February 2020.

This is under the strong assumption that there will be no major audit related delays etc.

Should I insist on starting the GC process sooner?

Or is this timeline just fine?

 

What happens if I change employer again. Will the H1b extension happen for another 3 years. So lets say I join a new employer in September 2018, will the visa automatically be for until September 2021?

 

Thanks in advance!