Wouldn't hurt if we replied, would it?
Each has his/her own definition, I'm sure. Some would consider themselves successful once they become rich, some when they're simply happy with their family. But most of us would rather we had both, right?
Mine is this, though: I would consider myself truly successful once I see my children successful in their own rights. I just need to see them happy and fulfilled themselves. After all, everything I do, I do it for them. Seeing them happy would be seeing the fruits of my labor not having gone to waste.