What Doesn't Invalidate Wudu

1. Drinking or Eating

The Messenger of Allah drank some milk and he did not rinse his mouth nor did he perform ablution, and he offered the prayer. [Dawud, Narrated Anas ibn Malik]

2. Kissing a mahram woman (such as your wife)

'Aishah related that the Messenger of Allah kissed her while he was fasting and said, "Kissing does not nullify the ablution, nor does it break the fast." [Related by Ishaq ibn Rahawaih and al-Bazzar with a good chain. Evaluating its authenticity, 'Abdul-Haqq says, "I do not know of any defect in the hadith that could cause its rejection."]

3. Laughing

Laughing does not invalidate wudu. Laughing loudly during salah, however, does invalidate the salah.

4. Vomiting

5. Changing a baby's diaper

Just wash your hands after changing the diaper.

6. People with unusual circumstances

(i.e. women with "prolonged flows of blood"), people who cannot control their urine, people with flatulence, and so on, should perform one ablution for each prayer whether their problem exists all or part of the time. Their prayers will be acceptable even while their problems are occurring.

7. Talking During Wudu