I use a variety of tools to help me run my roleplaying games. These vary from basic lists of names, to elaborate combat managers. While there are great benefits to these tools, there are some pitfalls that a game master must know of and attempt to mitigate as much as possible.
One of my programs is a client/server battle map program creatively titled MapTools. With it, I can build battle maps of every encounter location, set up tokens for monsters & players, manage dungeon exploration, etc. It takes map management time and either shifts it to before the game or eliminates it completely. On the surface, a complete win.
The problem is that this can limit you. MapTools works great with pre-generated maps; creating new maps in the middle of a game is problematic. When your game takes a new direction, you can not easily whip up something new. Suddenly, there is zero chance of an encounter at the new location. Similar, even for pre-designed locations, the lack of a map tips your players that there is nothing to be concerned about combat wise.
For planned locations, the dungeon master has two options. The first involves only bringing up the map once initiative is being rolled. By holding out until the last possible moment, you keep your players guessing about the danger.
Another option is to go to the other extreme: All locations have maps. Any place you plan on visiting gets a map. This creates a level of consistency throughout the experience. Locations can be visually explored, even when no combat will be taking place. It also gives you flexibility to turn an encounter you thought would be non-combat into one if the need arises. Similarly, combat encounters can more easily shift to non-combat ones as well.
Neither of the above directly address the problem of unexpected locations. The first solution hides your lack of maps. As long as you prevent the situation from devolving into combat, the players will never know. The second makes the problem worse; the lack of map instantly becomes apparent. To resolve this problem, you can put together a series of generic maps. If you put together an inn, a house, a store, a street, and exterior road, etc. could cover those new locations. They also could easily be reused in future adventures so they are not wasted effort.
Knowing the weaknesses of your tool is vital to using them efficiency. The first step to solving the problem is understanding them. The weaknesses of MapTools can be dealt with by planning a consistent method of map presentation. Either showing no maps until needed or creating maps for all situations both enable the maps to be used without tipping any hand toward the direction an encounter could take. This will keep your players on their toes, ready for anything.
And as a game master, there is nothing more fun than a group of nervous players.
-That is all.