Results can be almost instantaneous but much depends on the proper setup, the phrases which are used and on the complexity of the problem.

In some cases people may even feel worse. Tapping may trigger what is called 'aspects'. They are issues which are related to the problem but are not immediately seen as a primary problem, but they have to be tapped on in turn.

Example: Tapping on a money issue, sales not being what one wishes them to be.
Aspects of this may be insufficient product knowledge, or lack of people skills, or insufficient confidence, or an aversion to selling, etc. Tapping on the 'primary' issue will not be effective until all the aspects are resolved. However, skillful tapping on the money problem should bring up the various aspects fairly quickly and then they can be dealt with.