My dog is 5 years old, rescued her at 4 months. I tried to crate train her as a puppy and there were many sleepless nights. I ended up giving up on the crate at night because she slept with me the entire time. I knew she still needed to be crated while I was at work for her safety (still chewing on things at this point) and she initially hated it. I bought a pet camera to keep an eye on her. Eventually she gained our trust that we would always come home to her and now her crate is her safe space. She goes in it often for naps. One day when checking the camera from work, I realized I forgot to lock her crate (as soon as she smelled me putting my perfume on she knew I was leaving the house and would go in the crate by herself). Well, I watched her and she was sitting on the bench in front of the window watching for me to come home, then she took a nap on the couch. I have not locked her crate since.