1. Cleanse after use: It is essential to clean your bamboo chasen after every use. Wash it under running water with a mild detergent or soap, and then rinse thoroughly. Use a soft cloth or towel to wipe it dry.

2. Store in a dry place: Always store your bamboo chasen in a dry and cool place. Avoid exposure to direct sunlight and wettish areas. Do not store in the refrigerator or freezer.

3. Avoid high temperatures: Do not expose your bamboo chasen to high temperatures or heat sources such as stovetops, ovens, or microwaves, as this can damage the bamboo.

4. Soak in hot water: Soaking in hot water (not boiling water) for about 5 minutes, once a month or so, can help to rejuvenate the bamboo and extend its lifespan. This will also help to remove any stubborn tea stains or residue.

5. Use gently: When using your bamboo chasen, use gently and do not apply excessive pressure. This can cause the bamboo tines to break or loosen from the main handle.

6. Replace when necessary: Despite proper care, bamboo chasens will eventually wear out and need to be replaced. A well-maintained chasen can last up to six months to one year, but it may end sooner if used frequently. Replace it when you notice tines breaking or warping.