I had to realize that I know nothing about sampradayas thus I have a lot of questions, like

Are sampradayas important in a Hindu‘s daily life?
If you meet someone do you ask for her/his sampradaya?
I know a little about gotra that means, that every Hindu has a root to a rishi. Does similarly every Hindu have a root to a sampradaya?
Do you get the sampradaya by birth or by initiation?
Does a guru accept a sadhaka from another sampradaya?
Can one change from one to another sampradaya?
Are sampradayas connected to varnas?

Please help to expand my knowledge.