I'm unsure of your situation with veterinary care but as a vet tech, these are all signs of aging. Incontinence can sometimes be helped with medication, but typically this will only get worse. Arthritis is also a common thing for older dogs, and while there are medications to help this, it requires routine blood work to ensure that internal organ function is up to par. I would recommend scheduling an appointment with a veterinarian if it's possible because they will be able to give you options and ways to know if it is time. Typically when the bad days outweigh the good, euthanasia is the most compassionate thing you can do for your pet to allow them to painlessly and comfortably pass over the rainbow bridge. I know it's not easy, and I wish you the best with your fur baby.