Gaskets are found most commonly in mechanical applications and are placed between two connecting parts that are under pressure to prevent and limit any leakage of fluids traveling between parts in a system. They are used in the plumbing and automotive industries more than any other. Engines and plumbing systems can be very complex and everything must be in working order so the system as a whole can run smoothly. Gaskets are an important role in any system. For example, if a gasket was broken that connected the fuel line to the engine, gas would never be able to travel through the system to get to the engine in order to start it. This leaves you with a non working engine that will not get you anywhere.
I have previously worked at a marine supply store and have seen the importance of these gaskets in marine engines. A boater can not even take his boat out on the water if he or she needs a new gasket. If a broken one is used it can potentially harm the engine as a whole and lead to even bigger problems if the gasket is not replaced. These gaskets come particular to the type, year, brand and model of the engine you have. This makes it simple for anyone to replace with minimal help. Cost is not an issue as most gaskets are rather inexpensive to replace. It is not a bad idea to change them every couple of years anyways just to ensure tight seals in any system. One would not want to be left with a leak of gas, waste water or any type of fluid because it can potentially be harmful for contact and even to the environment. If you maintain your gaskets they will give your equipment a better longer lasting life.