Shaykh Muhammad ‘Awwamah (hafizahullah) says:
On one occasion, Imam Sufyan Thawri (rahimahullah) was with two of his students. One of them noticed that the other had long nails which needed trimming. He said to him: “Trim your nails.” He replied: “Insha Allah, tomorrow or the day after will be Friday, I will trim my nails on Friday.”

Imam Sufyan Thawri said to him:
“Do not delay the practice of the Sunnah for anything.”

[Shaykh (hafizahullah) comments:] This is a unique type of guidance; do not delay the practice of the Sunnah for anything.

Reflection
Shaykh (hafizahullah) once explained this principle and clarified that while removing nails and hair on a Friday is a recommended Sunnah, it is a mistake to believe this is the only time for it. To remove these from the body on a Friday is indeed a Sunnah. However, the overriding principle in the Sunnah is that these should not be allowed to grow excessively long. Hence, one should not delay their removal. They should be taken care of as soon as the need to do so arises. There should be no hesitation in putting every other Sunnah into practice as well.