Staffordshire Bull Terrier leg/joint problems

I know that people are quick to say either take to vets or why have you waited so long etc but sometimes there is no cause or issue(at least not diagnosed anyway) and things can clear up almost as quickly as they started.
I used to have a dog that suddenly started to drink excessively (for her)(bowl fulls everyday) After a week of this went to the vets, dog was examined, had blood tests, urine tests etc, nothing found in any shape or form. Another two weeks and things were back to normal. Obviously no-one wants their animals to suffer but sometimes these things just happen and then disappear again.