Depending on the wood detailing that you're doing, you have the option of using hand routers or a more conventional router that is table mounted for your wood work.
When to Use a Router
Routers allow you to make finished edges and design shapes in your wood working projects. Routers are also useful if you need to cut any holes or do any contouring.
When to Use Hand Routers
If the wood work that you are doing is delicate and on the smaller side, then you will want to use a handheld router. Because you have complete control over them, hand routers offer more control and diversity of cut that a conventional router. So if you are attempting to cut small holes, shapes or designs in your wood, a hand router will make the job a lot easier.
A down side of using hand routers instead of a conventional router is safety. Because a standard router is attached to a table, it is more stable and injury is less likely.
When to Use a Conventional Router
If you are working with larger and bulkier pieces of wood, or your cuts are going to be larger, then you may want to use a conventional router to do your routing.