It depends whom is home. My dog is also getting older, her back is hurt and she has arthritis. She will sleep on the rocker recliner in my wifes bedroom, ( should be ours ) but due to lifestyle & working hours .... I just sleep in the man cave ( lower level. ) Our ( Alli ) will also follow the sun spot around in the living room , it moves thru the upper level windows thru the day and she will pick a warm spot. Or by our fireplace, and every once in a while she will get caught on our nice & expensive leather couch. That is until she hears me coming, jumps down fast ... then knocks the vase off the coffee table.... what a hoot !
I used to come in the house and start feeling for warm spots on the furniture, each time her ears would get lower & lower...LOL