Answer

In Jain tradition, Sādhu Vandana is generally done when one respectfully meets a Jain Sādhu or Sādhvī.

Common appropriate timings are:

• Morning after completing personal daily duties and becoming clean.
• During the day when visiting Upāśray, Sthānak, or the place where Sādhu-Sādhvīs are staying.
• Before taking guidance, doing pratikraman, swādhyāy, or religious discussion with them.

Important Point

Sādhu Vandana should be done with:

• Clean body and respectful mind
• Humility and devotion
• Proper maryādā according to your Jain tradition

It is generally not done casually or without reverence.

Takeaway

There is no single universal clock-time for Sādhu Vandana. The right time is when you respectfully come before Sādhu-Sādhvīs, especially in the morning or during a proper religious visit.