Some women have the custom to light an additional shabbat candle for every week which, for whatever reason, they did not have a chance to light shabbat candles in the past. For example, if a woman with 2 kids did not light candles on 3 occasions at various times in the past, she would light a total of 7 candles (2 + 2 kids + 3 for missed weeks) every shabbat, indefinitely. One woman I know who is newly observant (ba'al teshuva) only lights additional candles for weeks she missed starting when she became observant. Where did this custom originate? What is the basis for the custom? Is there a limit as to how many additional candles one should light, both in terms of number of additional candles per week and in how long you should persist in lighting the additional candles? Is there a basis for not counting the weeks before you became observant? Any other "exceptions"?
This is mentioned in the following places. Darchei Moshe 263:1, Rama 1, Shulchan Aruch HaRav 1, Chayai Adam Shabbos 5:13, Kitzur Shulchan Aruch 75:14, Aruch HaShulchan 11, Kaf HaChaim 10. If she forgot many times then she adds for each time she forgot Magen Avraham 3, Shulchan Aruch Harav 1, Chayai Adam ibid, Kitzur Shulchan Aruch 75:14, Mishnah Berurah 7, Aruch HaShulchan ibid.
The reason for this, is that it is a (Knas) punishment in order that she should not forget.
If I remember, one should not be punished if one does not know better but when one becomes observant to the orthodox ways — you might say enlightened to the knowledge of the belief and why it is done — then I can see one having to make up for one not doing what one was supposed to do. But that`s really all I can remember.