This thread elicited a lot of responses, but I think I might have a little bit to add.

If you get out at 18, you're not necessarily giving up your AD retirement. If you really want to chase it, it's not that hard to find a Reserve job with man-days to give. Worse comes to worse, you can always raise your hand for an Al-Udied CAOC gig and knock out 4-5 months at a time.

I don't know where this 6 year reserve thing comes from. I've never heard that rule in the USAFR. If you qualify for the AD retirement, I'm pretty sure that the same gal in Denver who handles AD retirements handles Reserve AD retirments. The money all comes from the same pot and there's no difference between AD and Reserve once you have 20 years of active duty days.

Even if you've been passed over in the AD you can still make 0-5 in the reserve.

IF you can get an airline job and have a Guard/Reserve job lined up, and they are collocated or the commute is do-able, my advice would be to separate. (Always live at your military job and commute to your airline, if you get a choice).

If you don't have those lined up, then stay on AD.

My story: I got out at well over 19 years AD time, hired by SWA and a Reserve unit. If I'd waited until I had 20 years to get out, I'd be out of a job since no one is hiring now. Once my probationary year is over I can do as many man days as I want. My plan is to hold onto my reserve job until my airline job is a little more secure and my schedule a little more under control and then retire...on my terms and at a time of my choosing. If the man-days start to dry up, I could raise my hand for a single AEF and get to an AD retirement.