How long does it take to get the 1199A (Direct Deposit) form filled out by USAA?

Yes, you can still do direct deposit the old fashioned way with a form. Lets drag you and everyone else kicking and screaming into the 21st Century and go to Mypay (or DFAS.mil) and update your bank info online. Generally, all you need are the routing number and your account number. Veterans drawing VA Disability can also change bank accounts the fast way using ebenefits or VA.gov for quicker processing. Best of Luck!

I had done this awhile ago, and I was able to get it back in the same day -- I started the process first thing in the morning, though. I expect the process really shouldn't take more than 24-48 hours max.