I mentioned this on another post. In the US, they seem to be more into counting 10 kicks in two hours, not 10 kicks in one day. So the American Congress of Obstetricians and Gynecologistssites recommend it, and sites like this go on about it.
We seem more chilled out here in the UK. But I prefer to err on the side of caution so I always aim to feel 10 kicks / movements etc in 2 hours at some point in the day (ideally, in 2-hour sessions twice a day) and I always do, even on quiet days.