>>717675347 (OP)
In moderation. Although some research shows a tenuous link between caffeine and a reduction in the risk of dementia, the results are inconclusive, and too much coffee can and will lead to unpleasant health effects, specially if trying to quit a caffeine addiction.
At the end of the day, there are no long terms health complications of any kinds as far as I understand, so don't worry too much about it.