The frequency of sharpening a sword depends on several factors, including the type of sword, the frequency and intensity of use, and the specific requirements of the user. Here are some general considerations:

1. Intensity of Use: Swords used for cutting, slicing, or combat training will experience more wear and dulling compared to swords that are purely for display or occasional use. If a sword is regularly used for cutting practice or in martial arts, it may require more frequent sharpening.
2. Blade Hardness: Different types of steel have varying levels of hardness and edge retention. Harder steels tend to hold their edge longer, while softer steels may require more frequent sharpening. The specific type of steel and its heat treatment can affect the blade's durability and sharpness.
3. Cutting Materials: The objects being cut can also influence the frequency of sharpening. Cutting softer materials, such as straw or bamboo, will have less impact on the blade's sharpness compared to cutting harder materials like bone or thick targets.
4. Maintenance and Care: Proper maintenance, such as regular cleaning, drying, and oiling, can help preserve the sharpness of a sword. Neglecting maintenance can lead to faster dulling and the need for more frequent sharpening.

As a general guideline, swords used for cutting purposes may benefit from sharpening every few months to once a year, depending on the factors mentioned above. However, it's important to assess the sharpness of the blade regularly and sharpen as needed rather than following a rigid schedule.

Keep in mind that sharpening a sword requires skill and the use of appropriate sharpening tools. It is recommended to consult with a professional bladesmith, swordsmith, or experienced sharpener to ensure proper sharpening techniques and the preservation of the sword's structural integrity.