I haven't purchased tartar sauce in many years. We do not like any hint of sweetness, preferring the combination of dill pickle, lemon, onion and Worcestershire to flavor the sauce. This will keep a long time in the refrigerator.
Note to World Tour participants - this recipe is included in the British category. Similar sauce recipes (making the mayonnaise from scratch, of course) go back to Medieval times, and have been found in British books as early as 1685. It's also wonderful served with fish and chips, if you aren't very fond of malt vinegar.