The phrase "case by case" is usually used to mean separate and unique. For example, people often use the phrase "case-by-case basis." This means each case is examined based on its own merits rather than all cases being decided in a more general manner. Often, this phrase is used when discussing financial matters, and a person may state, for instance, that financial aid applications are considered on a case-by-case basis. People do, however, use "case by case" when discussing a full range of other matters as well.
Though people sometimes make decisions in a general way, when each case is considered individually and based on its unique merits, a person may refer to the decision-making process as case by case. There are many different things that might bear deciding on a case-by-case basis; a person may consider awards, punishments, help, and treatment in this manner, for instance. Sometimes price is decided on case-by-case basis as well. For example, if an individual is selling items that are unique, he may set prices case by case because no two items are exactly alike.
It may help to consider the law when trying to understand what "case by case" means. In many matters, laws apply to every person in a jurisdiction. For example, exceeding the speed limit is against the law no matter which non-law enforcement person does it. A police officer does not have to analyze the circumstances that led the person to speed when deciding whether or not to give that person a ticket. If extenuating circumstances were involved in a legal matter, however, a police officer or judge may sometimes consider the case with these circumstances in mind.
Often, people stand to benefit when a matter is considered on a case-by-case basis. This is due to the fact that many rules and regulations are often so strict that they seem unfair to a person who has a special circumstance to consider. Instead of being categorized with a general population of people who may face very different circumstances, a person might have a much better chance of getting a fair decision when his unique circumstances are considered instead.
Sometimes decisions are made based on general rules, laws, or regulations, but appeals are then handled based on the unique factors in a case. For instance, a financial aid department may deny a person's request for financial aid because his family's income is too high. When the person appeals, however, the financial aid department may then consider the applicant's special circumstances, such as the loss of a job or a recent bankruptcy.