Originally Posted by Ottopilot

No. You can bid any base at any time, but won't get it unless there is a vacancy and your seniority can hold it. Guam could be the exception. If you take the paid move, then you committ to two years, I think.

I bid IAH (because it was a shorter drive from CA), but didn't get it. A little after I finished training and moved, a new bid was out and I got it. I had already moved, so they let me stay in EWR.

You can also bid up in aircraft. If you are hired in the 737, you can bid a higher paying aircraft anytime. If you want to move down in pay, you have to wait 2 years. I did three type ratings my first year (737/757/767). Got my fourth rating around my 5th year (777). I wasn't chasing ratings, it just worked out that way.