Answer: Generally speaking yes, and certainly if it is causing you anxiety. Most owners would prefer to know what, if anything, wrong with their cat as soon as possible, and most vets would sooner that owner brought their animal for examination even for some trivial conditions rather to let a major illness go untreated.
Sometimes it is very clear from clinical signs that the animal is ill, for instance, when there is sudden change in temperament from an active, inquisitive cat to one that is listless and interested only on sleeping; or where blood is being passed (in the motions, urine or vomit); or where there is frequent sneezing with running eyes and nose.
At other time, when the cat appears normal in all respects save one, it can be difficult to decide whether this indicates the start of an illness or not. An isolated bout of coughing, or even vomiting, is not unusual for example from a small hairball. Temporary lameness may simply be the result of minor brushing after jumping, nor is a day’s in appetence uncommon, especially if the cat has been fed elsewhere. If the signs persist, certainly for longer then twenty-four hours, it would be wise to obtain a professional opinion. The more signs of the illness there are (from the list in the previous question), the more severe they are, the longer they persist, the more likely it is that the condition is of significance and should receive attention. Sometimes quiet serious injuries can produce few signs; for example, after a road accident there may be very little to see except some damage to the claws, some dirt and oil on the coat and pallor due to internal hemorrhage. Whenever you are in doubt the importance of changes you notice always ask your vet for advice.