The Rebbe's guidance on minhagim — Jewish and Chabad customs — and how to keep them:
The weight of custom. Established customs should be preserved, not cancelled (IK 3439), and longstanding customs should be respectfully investigated rather than dismissed (IK 3796). Follow established Chabad customs without hesitation or searching for doubts (IK 5635); following the customs set by the Alter Rebbe in prayer and tefillin is essential (IK 4700, 7012). Don't neglect established customs even while fulfilling mitzvos on time (IK 5751). Maintaining established minhagim strengthens unity (IK 5876), and one's own customs should always be kept peacefully, without causing disputes (IK 5788). Respect positive family customs where appropriate (IK 6552, 7346).
Transmitting customs. Collecting and publishing Chabad customs is valuable because it leads to practice; include all relevant notes, and record uncertainties honestly (IK 5536, 5636, 6572). Traditions such as letter forms are best passed on directly, from person to person (IK 2822, 3743). Keep prayer texts and customs accurate, without unauthorized changes (IK 6045). Adopting Nusach Ari is commendable but should be a lasting commitment (IK 6704, 3569).
Life-cycle customs. A baby girl is named at the first Torah reading after birth (IK 805, 7641, 8452); there is no Shalom Zachar for a girl (IK 8973). The upsherin is held on or near the third birthday, and ideally not during Sefirah but on Lag BaOmer (IK 3384, 2091, 8532, 9318). Tefillin are begun two months before bar mitzvah (IK 6234). Girls should begin lighting candles by age six, or even earlier, as soon as they are able (IK 9993, 6849). On wedding customs and dates, see IK 7161, 7410, 8509; on birthday customs, see IK 4082.
Customs through the year. On the order of Shehecheyanu and Leshev BaSukkah, see IK 1227; on the Rosh Hashanah apple, see IK 504, 7846; on Tractate Sotah during Sefirah, see IK 6897; on Nittel Nacht, see IK 4391, 5124; on Megillah customs, see IK 4597.
See also: Parenting – Naming a baby and the upsherin; Prayer – Nusach and customs; Halachah and custom – Asking a Rav.