ANSWER: You make a good point about not being responsible for whatever wrong may have been done in a previous life. You are not. Similarly, if, for example, you were a woman in a previous life and now you’re a man, you cannot say, “Well, I refuse to do mitzvot that only a man does.” What you were in the past is irrelevant now. We can only go by what we are now, even if we actually know for a fact some circumstance of a previous life (and certainly if we only surmise it). In that regard, what you do or who you were in a previous life is inconsequential.
Nevertheless, the Vilna Gaon writes [Commentary on Jonah]:
“The main thing [to keep in mind is that the purpose of reincarnation] is to effect the repair of a [negative] influence originating in a previous lifetime... [One way] to discern exactly what that negative influence is is to reflect upon the type of wrong your soul yearns after the most in this lifetime. That which you yearn after most is likely something you became habituated to in a previous life. And therefore pay attention to your vices. [They tell you exactly what you have to work on in this lifetime.] ...The main thing is to repair that which one stumbled in in a previous [life] ... How can one know what one stumbled in during a previous life? ... [Pay attention] to that particular sin one’s soul longs for greatly (for it was emblazened into the soul as a habit in the previous life). That’s why some people are drawn after one type of sin more than another. And that’s also why our Sages say that one must continually judge himself and weigh his actions..."
Note the subtle difference here between culpability and character improvement (tikkun). Consider yourself not responsible for any sins you may or may not have done in a previous life, if you even had one (and/or know about it). Nevertheless, since in principle, at least, a previous life may be impacting on your present life circumstance pay attention to your vices. Rather than limiting your free will, this information can, in theory, help it. For instance, you may feel you have no chance to overcome your lust for cheeseburgers. You may tell yourself you were born with this lust. It’s genetic. You feel you have no free will to oppose it. Every time you pass a McDonald’s you have to go in there and order a Big Mac.
However, if you take the Vilna Gaon’s teaching to heart, you may then come to realize that, although you are not now responsible for the sin of eating cheeseburgers in a previous life, you have this great lust as an opportunity for tikkun. Had it been just a regular lust for cheeseburgers your overcoming it may not be metaken (fix) the original weakness emblazoned into your soul. You don’t want this weakness when you are given your place in Eternity. So you were sent back here for the opportunity of eliminating the weakness; indeed, turning it into a strength. Overcoming this extra-powerful lust in this world turns your soul into a “body-builder’s” soul; perhaps even a “Mr. Universe” soul. It’s now stronger than it ever was. In any event, the point is that knowledge or even intuition about a past life can be a powerful aid to free will in this life.
Granted, it can theoretically create the opposite effect. A person may think, for example: What the heck; I’ll get it right in the next life. Or: If I didn’t get it right in the past what’s the point in trying in this life etc. The latter fear is the reason I believe the doctrine was restricted to Kabbalah, which ideally is reserved for select individuals of a higher spiritual standing to begin with.
Source: Jewish Soul Searching