Wiccans, generally, do not have a system where all the goodness and badness are stored until one point in time where all the good and bad points are judged.
The majority of wiccans believe in a concept called Karma which can be considered like a chemical equilibrium. People know the difference between right and wrong at an early stage of life, and know when they have broken it.
Although Karma is an eastern system it is useful as a "common frame of reference" for discussions with people not familiar with the concept or the system utilising a similar system.
Any bad action from a person will move this equilibrium in a negative point, and since all equilibriums don't like change to the system they will repel the change in any way possible. In Karmic terms there will be subtle changes in the environment, which occur immediately after the act, which eventually leads to an event, or series of events which are equal to the original negative deed.
Doing a good deed is the same.... change in energy system in a positive manner... change repelled... events lead to a good conclusion equal to the deed. Many witches believe this concept works in a 3 times the deed effect. Where you will get an equivalent change 3 times that of the original deed.
A trend in modern times is to reject the x3 rule, as it doesn't have any equivalent in nature and was one of Gardners extrapolations in the early days of the craft. The concept of Karma, in itself, is still generally believed in.
This concept, as well, is in fine equilibrium from having the practitioner developing dynamically and having development stagnating. Self preservation dictates the minimisation of events, which would be unpleasant. In any arena you choose the suppression of action can be more harmful than doing something. So it is in the occultic arena.
The laws of Karma, for anyone, is a system has its sphere of influence not entirely within observation or detection. That is one of the reasons that many occultists ignore the concept, due to its apparent Christian overtones of having a celestial "mark sheet" rather than recognising a delayed consequence, which propagates in a different manner.
The essence of the belief is that consequences will occur with any act that is partaken, whether mundane or magical. Taking responsibility for those actions, and the subsequent consequences without deflection is the trait. Negative actions are sometimes necessary for the greater good, so the consequences are taken as a mistake (learn from it and move on)