OK I am no expert on this for this was the first time ever having lil pups around and I started them out in the crate. The pups I had went right to it with no problem, I did have one pup that didn't care for it but once it was in their it was fine but I would wait til she fell sound asleep and I would put her in there but I did leave the door open unless I had to go to town. Just one thing though three years ago when my son brought home his boxer I never crated her didn't know nothing about it and she was a great puppy I would make sure she couldn't get anything to hurt her and I would go to town or outside at first and I would tell her to get up there and watch for me I would be right back, ( I have a recliner in front of a window) she would be sitting right their when I got back watching and waiting I wouldn't be gone long at all. after a while it was just natural for her to get up in the chair and watch for me when I left, still to this day I am never gone long and there is still nothing for her to get hurt on and she would wait for me in that chair looking out the window. Of course I had to pick up a roll of toilet paper once but I never forgot to put it where she couldn't reach it again. The phone was the only thing I ever had a problem with and it was because my sons girlfriend thought she had to call every five seconds and she would get annoyed with the ringing and chew on it other then that she was wonderful. But I would never leave all them puppies running loose in my house like that. (( and my son still hasn't brought her back yet and I still have the deaf male he is sweet as he can be and we are still working on NO ))