I understand that we spill wine for the plagues. People died, they went through hardship, and it was not their fault. But.... immediately after spilling wine for the plagues, we say that R' ...
As I recall, my mother usually discards the wine that is spilled at the Seder during the listing of the plagues. But I think she does this because, well, just because it's spilled wine and it is not ...
The custom among all Jews (as far as I know) is to spill a drip of wine for each of the plagues as they are mentioned in a list in the haggadah. This custom is not mentioned anywhere in the Talmud (as ...