Anywhere from 2 - 5 years
It depends on lot of factors like
Country -
Category EB2/EB3 ?
State where filed from ?
Region Vermont/TSC/CSC ..
Any Priority Date
And Luck ...
My observation : States like PA take less time for labor Whereas state like MA takes 1-2 years depeing upon EB2/EB3 & RIR category.
Once Labor & I-140 are cleared, the priority date plays role for applying 3rd stage (I-485). In 485 : factors like Medical Test, Finger Prints , RFE plays role in delaying your 485 process.
Luck plays a very IMPORTANT role .