The reason why the mobile phone battery can detect unhealthy state is also because it doesn't protect the mobile phone at all. Many people still charge while playing games, which is also a phenomenon that mobile phones are damaged. It is impossible for ordinary people to use Apple mobile phones to drop to 80% a year, because they don't care at all during use. If the battery is less than 80%, you can't meet your demand for mobile phones.
If you want to change the battery, you'd better change the original battery. The official said that battery replacement is not only guaranteed, but also has more stable performance. If you buy it in official website, you should send it to the place where you bought it. Some people don't want to change the battery for their mobile phones, because they think it takes hundreds of dollars to change the battery once, and these hundreds of dollars can buy a smart phone. However, using bad batteries may be dangerous at any time and anywhere, and there is no guarantee when using them.
Generally speaking, Apple's mobile phone is different from other mobile phones, and its life will be longer. You must learn to protect the battery of your mobile phone, and don't wait until it is lower than 10% or 20% to recharge. Be sure to keep the mobile phone above 50% at all times, so as not to seriously affect the battery of the mobile phone. Battery health is a kind of self-protection, so you must know how to use it to keep the battery stable.