[refurb]

I did a quick google search and it appears that in order to switch jobs you need to have your I-140 approved, so I did misspeak on that point.

However, since the labor certification part (PERM) is a much quicker process and you can file for your I-140 and I-485 concurrently, it's not unreasonable to assume that from the date you first start the process, you'll likely to be able to switch jobs after 2 years or so.

This is actually really important for those poor souls from India and China who have priority dates that still in the 90s and won't likely get the physical green card for at least 5 years if not longer.

One thing to keep in mind is that lawyers often disagree as to how to interpret the USCIS regulations. I've had lawyers say "Jesus! Don't even leave the country!" and others say "Yeah, it's fine to switch jobs, no problem." It just depends on how risk adverse they are.