The only guarantee is whatever The Plan is now, will change by the time it really matters to you.
e.g.: My Skipper at beginning of workups road period, May 2003: "The Plan is for our deployment next year to be a good-deal Med cruise. This Iraq thing'll be over by then."
In case you wonder, five of six months of that cruise were flying OIF ops. The other month was transit to and from the Gulf.