Establishing a minhag

Hi,

One who is strict in a particular matter three times, knowing that this is not a demand of the law and choosing to do it anyway, is now bound to continue the practice as though he had taken a vow.

One who is strict because he mistakenly believes this is the law, and then finds out otherwise, is not bound to continue his strict practice.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 1:46)

Have a great day,
Mordechai

Practicing a stringency

Hi,

One who observes a personal stringency should not do so in a way which will vary visibly from the practice of the community, even where he does this in order to satisfy a halachic doubt.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 5:20:19)

Have a great day,
Mordechai