The 99% Rule for Effect and Affect
99% of the time
effect is a noun, and
affect is a verb (have an effect on, influence).
If the question is "Should I use
effect or
affect?" the answer is given by the 99% rule 99% of the time.
And yes,
effect can be used as a verb (bring about, produce, create, cause), and
affect
can be used as a noun (feeling, emotion), but these usages are
comparatively much less frequent. For all practical purposes
these meanings can be dismissed from consideration in 99% of cases.
CJ