[Advaita-l] Doubts on Karma, future births etc.

[Suresh]

Namaste,

I am aware of the basics - that we all come into this world with some karma to work through. We may also accumulate more karma, so we must perform our duties in such a way that we dont - nishkama karma. Point is, Karma should be eliminated completely for us to realize our true nature and NOT take birth again.

My doubt is, How do we know that our karmas are being exhausted? Is there any tangible hint, or must we simply assume this? If a person still has greed or anger issues, lust etc., is it safe to assume that he has a long way to go, many more births? So we observe our own behavior and then conclude as to how much karma we have left? 

I am confused about this because there are many people who do sadhana for years but they remain the same (insofar as character or behavior is concerned) even after, say, 20 years. Does this mean their karmas are not being eliminated by their sadhana - meaning their sadhana is faulty - or does it mean these things cannot be empirically observed (and therefore no solid conclusion can be drawn)?

Any insights?

Suresh