Companionship. Loneliness can become an unwelcome companion as we age and can lead to depression as well as physical problems. Dogs mold their schedule and personality to you. They are never unavailable or off duty. Smaller dogs, in particular, can easily travel.

Having a routine. The routine of caring for a pet can bring structure and purpose to daily life. Maybe you don't always want to get out of bed, but your pet wants you to. Isn't that a good thing?

companionship (n) 伙伴关系 

mold (v) 使适合    

off duty 不当值 

routine (n) 常规   

structure (n) 周密安排、体系