Animal owners should regularly update their pet shampoo in order to prevent the onset of health issues, it has been claimed.
Patty Khuly, a US-based vet, expressed her belief that most healthy pets will only need a simple shampoo although there are certain considerations to take into account when purchasing the products.
Writing for USA Today, she said: "The only advice you should adhere to is to stick to the high quality brands - most supermarket brands are harsh and degrade in quality soon after opening.
"Some dogs and cats may even suffer severe skin reactions after bathing with months-old shampoo, so replenish your stash every four months, just in case."
Ms Khuly added that owners will only be required to bathe their dog around once or twice a month, although some terriers and dogs with wiry coats could go longer between baths.
Dogs with delicate skin, such as puppies and geriatric dogs, should be washed with a non-detergent-based shampoos, she stated.