Jasmine...my princess!

Jasmine is my 12+ old labradoodle puppy. I say puppy because to see her bound to the door to greet people, chase a tennis ball across the floor or catch her frisbee in the back yard, you'd think she was. But then when you look closely you see the clouded eyes and greying hair around her eyes, you can tell she is an old lady. Of course, since she lives in this house, she is also a foodie. She loves her marrow bones and is an absolute cheese fiend. She can be on the other side of the house and if I open up cheese, she comes running. However, she is a cheese snob. Once after a pot luck BBQ, someone had left American cheese (foreign to our house), so I decided to give her a slice. She took it in her mouth....and promptly spit out! That's my Jasmine.
She has always been a clock watcher in terms of her meals. She will let us know when it is time for breakfast and dinner (with dinner she starts bugging me as soon as I start cooking...even if that is 2 hours ahead of when she normally eats. She figures, "Lee's working in the kitchen, should be dinner time"!). About a week or so ago, she started letting her breakfast sit in her bowl and didn't eat it until later in the day. Then she stopped eating dinner. Everything else about her was normal: she ate her snacks (she gets a "treat" when she comes in the house), she had all her energy; she just seemed off her food. I put some homemade chicken broth on it and then she ate it, though she would lick up the broth and eat the food gradually over a few hours, actually taking some of the pieces out of the bowl, putting them aside, and then drinking the broth.
Now, adding the broth was fine with me, I wanted her to eat and I figured, what the heck, she's over 80 in human years, I don't blame her for being tired of this food. As reflects our "parenting" styles, I wanted to keep pampering her and my husband was more of the mindset to let the food sit and see how long it would take her to eat it. Well...she waited us out. Went over 24 hours without eating her meal. So fortunately we had our usual 5 week appointment with the vet yesterday (she has Addison's disease and needs a shot every 5 weeks). I described her behavior and he said it could be: 1) A lot of dogs as they get to this age turn away from their dry food because it hurts their teeth, so they start to prefer canned or softer food...however, she has excellent teeth..."the teeth of a 5 year old dog"; or 2) The dry food can go bad because the manufacturers do tend to coat it in fat so that it is more flavorful.
So after getting recommendations on food from my niece (a soon-to-be vet and owner of 3 dogs), dumping the remaining dry food in a giant ziploc bag, and scouring out the dog food bin, I went to our local pet store (Concord Pets) and bought both a small bag of her existing food and a small bag of a new food. When I explained to the store that I thought her food had gone bad, they said to please bring it back to them and they will refund my money as this does happen sometimes. They return the food to the manufacturer...so, good to know and what a great store!
The test came at dinner...would she shy away from the food again, or go for it. I gave her a small amount of the new batch of her usual food and hurray...she gobbled it up!
So lesson learned...trust your dog's nose and sense of taste!