I am not sure where I should ask this

, but I want an answer soon...and I know this is where you all look 1st--too much good stuff in this thread!!!!
As some of you know, I have two yorkies--Emmy and Oscar. Emmy is a little over a year and Oscar almost 13 weeks. Neither are what I would call "crate" babies. Both came home in a crate and never darkened the door of the crate again. Yes, they both have free roam in 3 rooms of the house. They don't want to ride in the crates in the car either.
Finally the QUESTION: Since I am home for the summer, I thought maybe I could "train" them to like the crates more or least get used to them somewhat. I just put both of them in their crates while I was vacuuming. You would have thought they were DYING!!! The barking, the moaning, the whining, the gnashing of the teeth...I am sure some of you know the sounds. I really want to get them more used to the crates--just in case we need to ever really use them and definitely for travel. Is is okay to just let them stay in the crates for a little bit (how many minutes???) every few hours during the day while I am home with them??? Thoughts??? I refuse to leave them in the crates while I am away during the day.
BTW, I left them in the crates while I came to ask and they are really quiet now....woohoo!!!