Potentially a little back story is helpful, but not so much that it sounds like excuses. If it's something like, "I didn't start my career until age 27 because I was in grad school" to account for lower savings and higher student loans, that's fine. Or "I'm disabled so I have to stay in my house that's equipped for my needs" kinds of things. But not, "I have to keep my Mazda sports car because I want to" kinds of things. :)