Bitcoin is created by the act of mining. Network members provide their computing power to perform calculations of mathematical problems and, for this reason, are rewarded with bitcoins. However, the more members you are mining, the greater the competition. Computers are very good at solving these mathematical problems, so the Bitcoin Network makes the solution more and more difficult, otherwise all bitcoins would be mined in a few minutes. That is why there are already many highly specialized hardware on the market for the sole purpose of mining bitcoins.
As new models are launched very often, everyone must optimize their mining equipment regularly to stay competitive. As soon as new mining equipment is released on the market, the former quickly become obsolete and therefore unprofitable. At the same time, this gradual development of technology increases the general difficulty of mining again. The result is an endless circle of constant need for optimization. This explains why it is essential to start with the best available hardware and immediately to profitably mine for as long as possible, not to waste a minute of precious mining time.