As long as you are ready to invest whatever effort until goal accomplished. Never accept failure. If for whatever reason you fail in a worthy goal, then you need to restructure, review your procedure, improve your skills and repeat increased and improved efforts until you reach your worthy goal.
Failure can become a routine, for that reason failure never should be accepted in human life. Failure is no option for a truly spiritual loving person. Success toward a spiritual goal is but the result of steady FULL efforts toward a loving and thus worthy goal by means of love and full efforts to improve love continuously until goal achieved. Until one with God.