I'd like to see where you read that, so I can better judge whether it is an idea I should look into. I think some people who feed a good high quality food might switch flavors, i.e. beef or chicken, to give the dog a little variety.
I didn't know that there was a health reason to switch foods every so often.. I switch my dog's food I'd say approximately every 6 months or so just because I feel like she may appreciate having a new flavor.. kind of like a person.. maybe it's just in my head but that's my thought process. Whenever I switch her food they I gradually introduce it, I start mixing it in with her old food and slowly turn her over to just eating the new food.
This is why it is advisable to switch
Rotating among ingredients, particularly protein sources, is another way to introduce variety to your dog's diet. Individual foods vary in the amount of amino acids, vitamins and minerals they contain. Routinely changing the protein and carbohydrate sources in the foods you use will provide a broader spectrum of nutrition. DogAware.com Articles: Switching Foods (Dog World Magazine)
Not only what Dawnben said but also according to Dr Karen Becker, switching proteins can lessen the chance of your dog developing allergies by exposing them to changes ..............see Dr Karen Becker's 'How to Control Dog Food Allergies'
That said, my girl has a tummy of iron so I change brands and proteins a lot! (I shop for the highest quality food at the best price!) Right now we are using Canine Caviar (4 stars on dogfood advisor!)
My dogs receive a really varied diet. They eat dry food, canned food, and raw meats all on a daily basis. We stick to the same dry food brand (Diamond) and switch flavors within the brand. With canned food they receive a different brand each day- and I'm always up for trying new brands so long as they are reputable and have a decent ingredient make-up. When it comes to raw meats they also receive different things each day. I'll feed them pretty much whatever my family is eating. If we're having chicken, the dogs do too. Beef? Dogs get that as well. (You get the picture). So I don't really switch brands for the dry food- but I definitely do for everything else my dogs eat. They're extremely healthy, have solid digestive systems, and haven't had really had upset stomachs in two or three years.
I'm another that tends to stick to the same brand of kibble while feeding different brands of canned food.
I feed Fromm kibble and switch between a few of the flavors and do so with every new bag of food.
I feed canned food as a topper and switch brands nearly every new can. I've used Taste of the Wild, Blue, Blue Wilderness, Wellness, PureBalance, Natural Balance, Merrick, Newman's Own, and I'm sure a few others.
I switch things up to give him variety, and to hopefully keep him from developing any more food sensitivities since he's sensitive to chicken and I suspect fish.
For 2 of my dogs, I change the protein every bag, but not the brand. It's far too hard to find brands I like that don't break the bank. I don't think changing brands is all that important, I think it's more about using a variety of proteins.
For Chess, she's on chicken and same brand the rest of her life, as it's the only protein and food that doesn't kick off her IBD.