Back in 2003 we started to laugh about discussions of BOG (Boots On Ground) which turned out to be not very funny when applied to Reserve and Guard personnel who were tied up so long at mobilization stations that their terms of service were practically over the day they arrived in theater.
Then the policy changed in Aug 2003 and shifted many people from their planned six month to 12. It was not fun. Predictability is critical to families, employers, individuasls which = everyone’s sanity.
Since then, all the services have tried to be as clear as possible: the clock starts running when your boots hit dirt in theater – Kuwait being the port of entry for most. Those coming as unit members are normally here for the duration and we speak of tour lengths. Right now that seems to be about 12 months for this theater.
For individual augmentees, it depends on their particular TCS (temporary change of station) orders. Active duty medical corps clinical positions are usually six months deployments. It avoids both burn out and skill degradation. RC/NG are 90 days. (the UK in contrast seems to do 6 weeks to 3 months for their clinical folks).
Me? I am on 180 days orders. Means I am out of theater toward the end of March. Unless, of course, things change. No changes known at the present.