For planing tasks, it is generally recommended to use a router with a minimum of 2 to 2.5 horsepower (HP). This ensures that the router has sufficient power to handle the demands of planing, especially when working with harder or denser materials. Additionally, routers with variable speed control, a plunge base for controlled cuts, and the ability to accommodate larger diameter bits (such as 1/2-inch or 1/4-inch shank) are beneficial for planing tasks. Choosing a well-built router designed for heavy-duty use will provide stability and durability during the planing process.