Rikki Tikki Traveller said:
If you applied the rule that if you roll equal to or under the number of terms served, you have to leave the career, then there is no way he should be able to serve for 15 terms.
At best, he could serve 11 terms
I pointed out this rule because it should help limit the number of terms but I don't believe 11 terms is 'the best' one could do. Either you or I am misinterpreting it, RT - or like many things in MGT, it can be interpreted multiple ways. Here is my take on things:
First. On the 11th term if a result of 12 is rolled, you can continue on to the 12th term. On the 12th term if a result of 12 is rolled you complete the term but can not continue in the career after.
Second. Keep in mind that it's the result. The roll with characteristic DM. In some instances a roll of 15 (or more - see 'Third' below ) is possible by rolling a 12 and having a +3 characteristic DM. In this case the characteristic for advancement in the Army is Edu or Int, depending on the specialization. Since there is no way I am aware of to increase a Army characters Int or Edu during their career, the character would have a max DM of +2. There is still a possibility of a character spending numerous terms in another career where their characteristics may be boosted then joining the Army.
Third. An Army event roll of 9 gives a +2 DM to the next advancement roll. An Army event roll of 11 gives a +4 to the next advancement roll.
It's not beyond possibility for a character taking anagathics to pick careers where survival (Even with just a +1 characteristic DM to start, surviving some career specialties is automatic except on a natural 2) and advancement is more likely. Work on maxing characteristics in the first couple careers so that the character can Qualify/Enlist, Survive and advance in additional careers. With the draft and drifter, a character could serve quite a large number of terms before finishing character generation.
For fun, maybe try to generate a 'ancient'

If you do, please document all the details of your chargen and post them.
Personally I've never played with anagathics. If I did, I think I'd also consider the Iron Man rule on page 40 and the term limiting rule Bense mentioned which is on page 36 - unless the game is designed for a group of 'superhuman' characters (with opponents who may also be 'superhuman' long term anagathics users).