The ISP should be able to tell you what your limits are. We were on the cheaper high speed plan (which really wasn't that fast at all, but still better than dial up), and the ISP told us that if we watched more than 9 or 10 movies at Netflix per month, it would eat up our allotment in a hurry. We would then have to pony up more cash to purchase another "block" of bandwidth at that point.