There is no easy answer to this question since while some dogs do indeed need to have their anal glands manually expressed once or twice a year, or even more often in more serious cases, some dogs never experience issues. Thus, the better question would be whether, not how often your dog’s glands need to be cleaned.You need to understand that the two anal glands that every dog has are designed to release a unique scent into its stool when the dog poops. For most dogs, these glands filled with liquid empty out with each defecation. Problems arise when the glands fail to empty and that can lead to build-up and in severe situations the glands may even rupture.You’ll be able to tell if your dog needs its glands cleaned if it gives you signs such as the ones we mentioned earlier: rubbing its behind on the carpet, licking or chewing the bottom area obsessively, and foul odors coming from your pet’s anal area.Apart from these, external factors can also make it necessary to express the glands manually. Loose stools and diarrhea, in particular, can have a big impact on the anal glands. Unlike normal stools that are hard enough to express the glands on the way out, loose stools can lead to a build-up of liquid inside the anal sacs.Furthermore, small breeds and dogs that have food allergies or that suffer from obesity may also need to have their glands expressed manually more often. There are also pets who are born with the glands positioned slightly out of place.It is hard to say just how often your dog’s glands will need to be cleaned or if it will ever need it since each pet has unique needs. As long as you keep a close eye on the behavior of your pet, you and the vet will be able to keep these kinds of problems at bay.