A. Whenever is convenient. Many people have the consecration about a year after the death, though some prefer a date at the end of the Sh’loshim (first 30 days) and others choose the end of the Shivah (first seven days).
Strictly speaking, no consecration ceremony is necessary, though it is a great act of piety and has psychological and spiritual value for the bereaved, as well as for family and friends.
The erection of a tombstone – with or without a consecration ceremony – derives from the example of Jacob who placed a monument over Rachel’s grave (Gen. 35:20). In II Samuel 18:18 we read that Absalom, during his lifetime, erected a tombstone for himself because he had no sons to maintain his memory or name.