Dry, canned or raw? All are fine choices, but each has its pros and cons. Dry dog food is convenient to store, but you should at least supplement with canned, raw or homemade food, according to experts such as the editors of Whole Dog Journal, "The Dog Bible" author Tracie Hotchner and DogAware.com's Mary Straus.
Canned food tends to be higher-meat, lower-carb and contains fewer preservatives than dry (because the canning process itself acts as a preservative). Canned dog food also lets dogs get more moisture from their food, which helps them stay properly hydrated and benefits the urinary tract. (By the way, kibble doesn't clean dogs' teeth, Whole Dog Journal says -- chewing raw bones does that.)
Raw food gets closest to dogs' wild diet. You can make it yourself, or buy convenient frozen or dehydrated raw food.
Which life stage? Only two life-stage designations have any real meaning: puppy and adult dog. Those are the only two regulated by AAFCO. Puppy formulas generally have more calories and protein. Products labeled "senior" or "large breed" simply meet requirements for regular adult food. There's nothing regulating those additional terms when they're used on dog food packaging.
Observe your dog carefully when trying a new food. Some dogs need more protein and some need less, just as some dogs need to eat more than others, depending on activity level. Look for changes in coat and skin, along with stool consistency.
Pet-food safety is a concern. Past and recent recalls of dog foods have spotlighted some major issues regarding pet foods and their ingredients. Recently, recalled pet foods contaminated with salmonella have also sickened pet owners who handled the food. Although the majority of foods are deemed safe, this is clearly an ongoing issue.