A critical point of these lists is that not every town will be able to support every one of those industries. Armorers, for example, are highly-specialized tradesfolk that will typically be present in only the largest gatherings of rich people. Those in smaller trade centers will need to travel to find an armorer. Similarly, every village may not have a blacksmith, but there will likely be at least one for every few villages to repair the day-to-day items. Farmers or other fundamental producers are likely to be found in virtually every hamlet.

Central place theory ( http://en.wikipedia.org/wiki/Central_place_theory for a useful overview ) is a useful starting point for helping to determine regional trade patterns; these trade patterns and a good idea of how large/rich your town is can help in understanding what's present in your town. Note that the ideal drawings shown in the above-referenced article assume a uniform landscape with no impediments to travel. Also note that the "distance" referenced is approximately a time-of-travel/energy-of-travel value. Barriers to travel such as large rivers, mountains, deserts, or even hostile local governments (under which oversized flying lizards can be broadly grouped) will all significantly affect the shape of the network; enhancements to travel such as good roads, navigable rivers, and even trade-friendly law enforcement groups will push the network shapes in the other direction. I know that I would much rather (and have) detour down a well-maintained and well-patrolled road than go a shorter distance through more dangerous territory, especially if takes about the same amount of time.