I don't have any traditions or formalities when it comes to photography, especially weddings. As for formal group shots on the wedding day, I shoot whats requested. Before the day, I ask my couples to think about what group shots they really want, if I'm going to start dictating and moving people around, and more importantly keeping people from the bar ;) then I want to make sure it's something my couples are actually interested in and want.
Some couples don't want any formal group shots; some want one or two and some half a dozen. Depending on your needs I'll be looking to spend around 10 to 15 minutes on group photos, so no time at all. The formals will be short and sweet, with added humour to speed things up a little and to get some great smiles and giggles along the way.