Hi all, I'm new to the forums. I wasn't sure where to post this. This forum seemed the most appropriate.

I used to work for the airline industry, but have left for a different career. Unfortunately, my time in aviation has left me bitten by the travel bug! I'm used to playing the non-rev game, but I'm completely new to the frequent flyer game.

Facts about me:

1) I live in Dallas. I plan on flying to a variety of destinations, so AA will probably become my preferred carrier.

2) I anticipate taking around 3-5 international trips a year for vacation, with a handful of weekend domestic flights thrown in for good measure.

3) I see myself flying above 50k miles a year, but probably less than 75k.

4) My main reason for being interested in a frequent flyer program is for savings. Perks like upgrades are nice, but essentially I'm looking to save money on travel that I plan on doing anyway.

Everything I've been reading online suggests that I should be a member of AAdvantage, which makes sense given I'll mostly be flying out of DFW. I've applied for a Citibank AAdvantage card, waiting to receive it in the mail.

However, I was planning a trip to ICN, when I found a $840 all in fare DFW-ICN via DTW on DL (this fare has since been cancelled - in fact, cheaper fares were available, but I would have been required to fly on days I couldn't fly). I purchased the fare.

This was significantly cheaper than DFW-ICN marketed by AA, or any other carrier for that matter. Somebody correct me if my thinking is wrong, but 15k miles is worth less than $500+ dollars, so I feel like I made the right move. On top of that, I signed up for a Gold Delta Skymiles card and instantly got 30k miles, as well as a $50 discount on my fare, which felt like icing on the cake.

I do not currently have miles earned on any other program at this time.

I have two questions:

1) Did I make the right decision? In the short term, I think it's clear I saved money on this particular flight, but am I losing in the long term by not keeping all of my travel on the same carrier?

2) (this is going to take some set up)

30k miles seemed like a good deal, plus I'll gain miles on the flight itself too. If I'm understanding this right, that alone is enough to redeem for a flight.

However, I don't plan on using DL long term. Skyteam has a great network, but as I said earlier, I live in Dallas, and AA/oneworld is usually going to be a more logical choice. After I redeem these earned miles, I anticipate largely using a Citibank card to earn miles on AA and cancelling the American Express Skymiles card.

If I run into another situation 6 months from now, where DL/another carrier is significantly chearper than AA, can I reapply and still get a big mileage bonus?

NOTE: I do NOT want to break any laws. If there is something illegal about cancelling a credit card and reapplying to regain miles, I definitely do not want to do so.

Mostly, I'm posting this to get advice from people with more experience doing this sort of thing than me. Thanks!