Able-Bodied Men Only
Khan didn’t want to build an army of people without the necessary skills to execute his plans. He only accepted able-bodied men into the army, and this rule meant that anybody older than 15 and younger than 70 was forced to join the fight if they had no physical or mental disabilities. Some historians suggest that this meant that one in six Mongol men ended up being a part of the army at some point.
No Regular Pay
The Mongols never received formal pay, which in any army setup would have caused some soldiers to be disgruntled. Khan had a strict rule about how his soldiers would be rewarded, which was controversial at first. By today’s standards, it would not have been enough to satisfy the soldiers over the long term. It did end up getting the job done, but nobody was allowed to ask for excessive wealth for their service to the community.