I asked myself "What do I always buy when it comes up on a mercenary roster?"

Simple answer is "anything I can't build myself" when I'm feeling rich, or "anything at all" when I just need bodies to stand in the way of arrows.

"Must haves," though include:

Longbows: Even if I'm playing England I buy them to stop them going over to the other side. Though I've since read that the AI doesn't use the merc roster so maybe that's a waste of time.

Druzhina Cavalry: Nothing like a long row of foot knights bought cheap and selling themselves dearly. Rubbish on horseback though.

Organ gun: The range is so pathetic you don't always get to use it, but oh boy, when you do...

Gallowglasses: Had a bunch of these guys chased into a forest by some Pronoiai Allagion so left them to rout or die. When I next checked that side of the battle it was the Byzantines who were routing and my gallowglasses - a little worse for wear - were in pursuit.

Turcopoles: Playing as the English you don't get a mounted skirmisher option - until you reach Outremer that is. Not the best horse archers there are, but handy for some factions.

Steppe Heavy Cavalry: slow, not as tough as the price tag suggests, but versatile. Again, great if you are playing a faction short on mounted skirmisher options.

Muwahid footsoldiers: Just got the hang of these in my last Almohad campaign. Versatile and swift-footed.