It takes Millie about an hour to play badminton every day.
=Millie spends about an hour (in) playing badminton every day.
=Millie spends about an hour on badminton every day.
It takes Millie about an hour to play badminton every day.
=Millie spends about an hour (in) playing badminton every day.
=Millie spends about an hour on badminton every day.