-a situation that is still true e.g. "I have always liked John." Here the Americans would use the present perfect because if they used the past simple (I always liked John), it would imply that I didn't like John any more or else that John was dead. (This last distinction is based on my own theory; I don't think you'll find it in a grammar book.)
If you are studying English for an exam, it would be better to stick to the British use of the present perfect. If not, obviously the American use is much easier to put into practice.
Student or Learner