I used to take 4,..now I take one 3 ball roller, 2 balls for strikes, and a spare ball. One reason is that there's just not enough room anymore, some of these bowlers are bringing up to 8 balls, they pile 'em everywhere, there's $10,000.00 worth of bowling balls per pair, and no way to walk to the approach without tripping over balls and bags. Plus with only 2 balls I have to rely a little more on skill, makes me think.