I leave their food out 24/7...BOTH kinds.
I actually started out with Beneful, and decided to offer Welness. I think it's a better food. Anyway...
I didn't do it like most do, where you start with a little of the new, and reduce the amount available of the old. I just set a bowl of Welness down beside the Beneful, let them eat what they wanted, and still am.
"They" decided that they would eat the Beneful in the mornings, and the Welness in the evening. I didn't decide when they would eat, they did, and they are as regular as a clock on their own.
So now, I feed two kinds, and just fill the bowls up when they get low.
It's SO nice to not have to worry about it, and let them do what they want.