The way I see it;
1) On a 12 year engagement and done 8 years or more - Worry!
2) Over 51 years old - Worry!
3) Average Joe - Worry!
4) Everyone else - Worry!
As has been stated this will impact on ALL NCA trades. The bottom line is we are a mere commodity that can be traded and if you don't cut the mustard they will look at binning you!
It really is time to build a solid case for your defence wherever you are - no one is indispensable. Its not pleasant, but it is the harsh reality of the modern Armed Forces.