Infrastructure jump

An infrastructure jump is when a nation saves enough income and/or aid to buy a set number of infrastructure levels (usually around 300) to avoid the net income loss.

Explanation of Infrastructure Jumps
Every time you go from having X999 amount of infrastructure to Y000 (ex. 1999-2000) of infrastructure, you experience a drastic increase in the cost and upkeep of infrastructure per unit. For example once you cross from 999 to 1000 infra, the infra cost and upkeep go up by 22%.

Because of these increases your nation experiences a relative income loss. So even though your gross income goes up, your net income actually suffers because of the disproportionately high rise in infrastructure upkeep bills.

Thus, to avoid this relative income loss, you must perform what is known as an infra jump. Infra jumps entail saving enough money to buy MINIMUM 200 units of infra in a single sitting in order to jump from say 999 to 1199 (or 2999 to 3199) infrastructure. At N199 (N = number between 1-5) your income and the rise in bill level have once again leveled off so there is no relative loss of income.