The complexity of the network (mining) is calculated from the performance of all devices that are currently mining. Cryptocurrency generates for its miners a certain amount for a certain period of time by itself. This amount is divided among all who mined it, in proportion to the performance of their hardware. In fact, this is a scheme of work only for the general pool (which is essentially our system), at the core everything works a little differently, but for ease of understanding, we will not go into all the technical details. To make it clearer let's give an example in dollars. For example, a cryptocurrency generates $1,000,000 per minute for its miners. If only one person is engaged in mining, then he receives $1,000,000 per minute. If 1,000,000 people are mining and everyone has the same speed, then everyone gets $1 per minute. Every miner does not have the same speed, therefore in real conditions, not every miner will get 1 dollar: someone more, someone less, depending on the performance of their hardware. Most often, difficulty jumps depend on the exchange rate of the coin. If the rate falls, some user begin to quit mining, due to this, the cryptocurrency income of those who did not quit grows. If the rate grows, the interest in mining this currency also grows - more miners are connected, due to this, the cryptocurrency income of all participants decreases, in other words mining becomes more difficult. Also, new people who have just learned about this type of earnings are constantly connected to mining. Due to the constant growth of new members, the income of each user decreases over time. In simple words, the earlier you started mining, the more profitable it is in the future, today you can mine more cryptocurrency than in a month in the same period of time.