Also to answer your question- United Captain awards can be held after being off of probation ( 1year) and have flown 500 hours in United. That is for NB 737 or 320. 75/76 in SFO as well. 777 or even 787 upgrades are currently 20-25 years away.
I think that in Delta upgrades are available within the first year.
From what I hear upgrades at American run currently at about 2-2 1/2 years for the narrow bodies.