When should one look at their nails during havdalah. Is it right before the bracha borei me’orei ha’aish, to make sure that they are close enough to the candle that it should not be a bracha livatala, or look at their nails after the bracha which seems to be the custom?
According to the Tur (298), the purpose of looking at one’s nails by the light of the candle is to ensure that one is close enough to derive benefit from the candle. In this case, one should clearly do so before the berachah.
The Mishnah Berurah (296:31) indeed rules that one should look at one’s fingernails before making the berachah.
However, the Kitzur Shulchan Aruch (96:3) writes that the custom is to look at one’s fingernails in the light of the flame after reciting the blessing, and this is a popular custom.
It is possible that this question will also depend on the dispute among rishonim as to whether the blessing is considered a blessing over the benefit one derives from the light (see Michtam, Pesachim 104), or a blessing of praise for the light (as most rishonim write).
If it is a blessing of praise, as most authorities write, there is room to argue that one should ‘benefit’ from the light (by holding out one’s fingernails) after the blessing.
Some hold out their fingers before the blessing, and keep them there until after the blessing, thereby fulfilling both opinions.