We are Individuals, Part of Klal Yisrael, and Human Beings
In the third chapter of Hilchot T'shuva, Rambam "suggests" that each of us imagine that he/she is precariously balanced between merits and demerits, and that one mitzva, act of kindness, good deed can tip the balance to the side of ZECHUT and Life. (And conversely...)

This imagined balance between life and death, between righteous and wicked, goes for individuals, for the Jewish People, and for the entire world. Imagined — because we do not know what the actual heavenly balance sheet says. We do not know how G-d keeps score. Rambam adds that mitzvot and sins are not counted at one point each. They each have their value which is completely incalculable by humans. This information belongs to the NISTAROT, the hidden things that are G-d's alone. 

This, at the same time, puts a tremendous burden on the shoulders of each of us - and - eases our burden as well.

On the one hand, to have the feeling that one's fate and that of the People of Israel and the entire world depends up one's next act. is an awesome responsibility that few can handle.

On the other hand, to know that one need not accomplish a total make-over of oneself, but that a slight improvement, a bit of T'shuva, a start on the path to self-improvement can lead us to being inscribed in the Book of Life, this can ease our burden and encourage and inspire us to greater quality and quantity of T'shuva.

Remember that we have the ability to be as great as Moshe Rabeinu, but are held accountable only in our striving to be better selves. And even if the ultimate question to be put before us will be, "Were you the best YOU that you could have been?", perhaps the yearly question we are asked each Rosh HaShana is, "Are you a better YOU than you were yesterday or the day before that?" Anticipating that kind of question should be an extra incentive to heed the Shofar's call to T'shuva.