When it comes to how often adult diapers should be changed after a bowel movement, the key is to keep the skin clean and dry to prevent skin irritation or infection. Here are some guidelines:

1. Change immediately: Diapers should be changed as soon as fecal incontinence occurs. Enzymes in feces can quickly begin to irritate the skin and may cause rashes or other skin problems.

2. Clean thoroughly: When changing a diaper, clean the area with warm water and a mild, fragrance-free soap, then gently pat the skin dry. Make sure the skin is completely dry before putting on a new diaper.

3. Use a protective cream: Consider applying a thin layer of skin protection cream, barrier cream or petroleum jelly to clean and dry skin to help protect it from moisture.

4. Choose the right product: Use an adult diaper that has good absorbency, is breathable, and preferably has a leak-proof design to reduce the number of changes while providing better skin protection.

5. Regular checking: Even if defecation does not occur, diapers should be checked regularly and changed as needed, especially at night or before prolonged activity, to ensure comfort and hygiene.

In conclusion, it is very important to change adult diapers in a timely manner in the event of a bowel movement, not only to help maintain personal hygiene, but also to prevent skin problems from occurring. If there are any special needs or questions, consulting a healthcare professional can provide more specific advice.