My experience.
On November 20, 2013, wife and I got the Moto X (1st gen), signed a new 2 year contract, changed to 10 GB More Everything plan. (my line was an upgrade, her line was new to the account).
On November 14, 2014, I found 2 old phones (Droid 2 Global and Galaxy S Fascinate), both 3G devices, and activated them against our lines. (Turning the X's into wifi-only devices, and ensuring that we get to keep them during the Turbo TradeIn program).
On November 15, 2014, we went to a VzW store with our Droid 2 and Fascinate in hand. (5 days before our 1-year anniversary)
- Explained that we wanted to trade them in towards Turbo's.
- Also explained that we wanted to switch to Edge for both lines, since the trade-in results in $25 discount per line per month for the life of the Edge program ($450 over 18 months for each line).
- The Fascinate worked without any issues. The rep was able to select Early Edge, along with the $25 discount, and my wife taking the 32GB Turbo Red, for an effective wash in monthly price.
- The Droid2Global gave them issues.. not sure why, but they eventually did a trade-in over-ride to force Early Edge, and the $25 discount. I choose the 64GB Turbo, for an effective $3 more per month.
Oh, and on top of all that, we also took advantage of the new pricing for the More Everything plans, and now have the 10GB plan for $20 less than we were paying.
At this point, we now have brand new phones.. much better battery life, .. an effective $17 drop in monthly cost, and have the ability switch to new device in 18 months. Now, VzW could easily not offer the $25 discount next time around... so.. we'll have to revisit that when the time comes.. but, I see this as a win for now.