Thanks again chaps.
NOD, let me have a got at your algorithm..
Very few retirements for next four years, since max age 58 and average retirement 62.
Even spread from 25 to 58, giving 33 years. So plus four, that's 37.
Hard for me to gauge the whole ratio of SH/LH migrations, as well as P1/P2 ratio, but I'm going to make a blind guess that the decreasing P1/P2 ratio might be compensated for by the amount of P1s going part time and P2s not taking SH commands.
So 37/2= 19-ish. To that I will apply what seems to have been the spread between SH/LH time to command: 7 years.
Final guess for SH command 19-7=12. Minimum, of course.
Like you said, it's not all about the money. But I need data for financial planning. My house is paid off but I have two young children and a wife who is considering starting a business. When did it all get so complicated?
Cheers,
P