Have you ever experienced that your Raspberry Pi no longer wears boots? The red and yellow lights flash several times and then stop? These are the classic symptoms of a damaged SD card.
The first thing you can do is to regularly back up your SD card BEFORE it is damaged. If you spend hours configuring an SD card, save it. Do you modify your software? Go back to it. This will save you a lot of time if you damage or destroy the SD card.
Similarly, incorrect shutdown of the Raspberry Pi often results in damage to the operating system. To stop safely, you must open a command line and type the following command: