Thank you for the advice. I think bid for the now and not worry too much about later is good advice. And I was talking about Delta specifically.

As far as defining "easily" and "difficult" I actually was talking more along the lines of how often Delta will allow you to switch aircraft (2 year freeze after 2nd aircraft answered that question partially) and I was also talking about if they run new bids frequently. For example, at my current (soon to be former) airline they went quite awhile without running a new award so everyone that was on one aircraft was stuck on that and everyone on the other aircraft was stuck on that until we saw movement, which lasted a couple years +. So I was not sure if sometimes years go by without opportunities to bid over to other aircraft at Delta.

Thank you