How do you keep up with the AI (troop building)

[Kjeld]

Thanks for all the answers thus far.
Actually, I am rarely behind (or at least, that much behind ) the AIs in the # of provinces owned, or income.

However, I am starting to realize that I tend to put too many eggs in the same basket. I am often tempted to make "superstacks" of very powerful troops, but I am starting to think that more numerous armies, with a lower but decent number of elite troops/mage backing up lower quality troops might allow me to both expand faster, and control marauding enemy armies. I, however, always fear to spread my forces too thin.

Which leads to a question : how many armies and of what strength do you all feel comfortable with ?