Pilot Priority
The ADF is always looking for high quality applicants to fill pilot positions and so it will always be advertised as "priority". Even though supply and demand of applicants will vary over time, in order to ensure quality at all times, you always have to look for it. If you try an "off and on" approach, and try to match it with future needs, you end up worse off. You'll notice other positions in the ADF that require quality applicants will also be advertised as priority - virtually all the time, for the same reasons. Remember, there's always jobs going - sometimes more and sometimes less.
PS: The same applies to applicants as well - don't try and time your application!! Apply when you feel you're the best you can be and don't worry about the rest!!