You actually arrange it with the base manager, before the monthly bid period opens. You can submit your yearly schedule if you want or go month to month. If you're going on TDYs or a longer term leave that requires orders, you submit those. I never had any problems with getting time off, even on a few occasions where I forgot to submit the request until during, or even after, the bid period. They've also been pretty cool about getting me the time off even if I didn't have orders in hand by bidding time but knew they were on the way. The base manager in MSP is a former Air Force crewmember, so he "gets it." I have heard that guys in other bases have had occasional issues. With all that said, even though the law says they HAVE to give you the time off for military duty, it doesn't mean you can call them up the day before a TDY you've known about for weeks and not expect a little blowback.