Here are the corrections needed for each sentence:

1. **Mistake:** "are" should be removed.
**Correction:** "Having leisure activities is truly important to the elderly."

2. **Mistake:** "should to follow" should be corrected to "should follow".
**Correction:** "Some people think young people should follow the tradition of the society."

3. **Mistake:** "interesting" should be changed to "interested".
**Correction:** "I am very interested in problems caused by pollution."

4. **Mistake:** "to the recycling program" should be corrected to "in the recycling program."
**Correction:** "You should participate in the recycling program."

5. **Mistake:** There is no mistake in this sentence; it's correct as is.
**Correction:** "If you work hard, you would be successful in anything you do."

Revised sentences:
1. "Having leisure activities is truly important to the elderly."
2. "Some people think young people should follow the tradition of the society."
3. "I am very interested in problems caused by pollution."
4. "You should participate in the recycling program."
5. "If you work hard, you would be successful in anything you do."