It really really varies. I tend to prefer minimal quilting on a lot of my quilts; on those I'll use a batting that supports wide distances and do some SITD - I'm not a perfectionist and am convinced my small waverings are never noticed so those go very quick - an hour or two. Other quilts where I want to do something more intricate it can take me a couple weekends to quilt a lap quilt. I don't do super-dense quilting, ever, so I'm sure that would take even longer.