Contra dances are usually done 7 to 10 times through. A three couple set dance will be done 3 or 6 times through. The dancers Most of the clubs and dances I go to have very few young people dancing at them. This is a vicious circle that shows no signs of being broken at the moment. Most of the under 40s are involved in the ceilidh scene rather than the dance scene.
Many clubs are very couple based.
People come along with their partner and dance with their partner all evening. The bands Bands are often accordion led. A typical three piece line up is accordion, fiddle and guitar. This means that the bands usually work from printed music, although the better musicians will use this only as a guide and improvise arrangements on the fly. Bands are also expected to be able to include new tunes in their repertoire at short notice.