Just like horses provide a map speed bonus, what if you could buy other items in town markets that provide bonuses to other stats?
For example: For 10,000 gold you could buy an expert trainer who increases your chance of hourly recruitment or a navigator who increases your movement speed at sea when we get boats. Or maybe something like a "trading guild membership" for 30k that increase your chance to create trade goods to 100% per hour and gives an extra bonus to the selling price.