I Only want to add something. I manage to finish complain without hiring mercs a single time. I never really had any money for that. Instead, I had 10 persuasions and work on good relationships with martial, outstanding and good-natured lords from the start. I easily get 10 vassals very fast after creating a kingdom. I probably should hire a company to hold my cities, but I was broke.
After my personal army hit 550 I did not need to be a marshal any longer. I give marshalship to good lord, give him some good troops and let them keep the opponent in bay when I take castles with just my personal army. And i did not get many gems did not have any noldors in an army, just unimproved knights and sergeants, adventures and high-level standard troops to bulk up.
I was still loosing 100K/week just from my army and cities I hold, but with occasional lord capture, I did keep myself afloat.