We, the family of Muhammad ﷺ, would go for a whole month without lighting a fire, having nothing but dates and water. Ibn Numayr, however, said, "We would remain for a month."
حدثنا أبو بكر بن أبي شيبة حدثنا عبد الله بن نمير وأبو أسامة عن هشام بن عروة عن أبيه
إن كنا آل محمد ﷺ لنمكث شهرا ما نوقد فيه بنار ما هو إلا التمر والماء إلا أن ابن نمير قال نلبث شهرا
Sourcing, sahih. See no. 4142 in this book, and Muslim, no. 26/2972b, from Ibn Abu Shayba with the same, and Bukhari transmitted it, no. 6458, from the hadith of Hisham with the same, and both Bukhari, no. 2567, 6459, and Muslim, no. 28/2972, and others transmitted it from the hadith of Yazid bin Ruman, from Urwa, with the same, at greater length.