Injections and Leakages
Let's talk about injections and leakages. When you look at the circular flow model more closely, you find that there are things that inject money into the economy and other things that leak out of the economy. Injections into the economy include investment, government purchases and exports while leakages include savings, taxes and imports.
Savings leaks out to borrowers as it goes through the banking system, and borrowers use the money to buy goods and services, which then injects the money back into the circular flow. Government taxes leak out of the circular flow model, and then government spending injects them back into the economy. Imports leak out of the economy because the money in our country that's used to buy imports from other countries goes out of our economy and into their hands. Exports, on the other hand, are an injection because we earn income from the goods and services we export to other countries.