This isn't always the case. Some cats that run away will never come back. However, some cats go out during the day and return at night, while others may stay out for a month or even longer. This depends not only on the cat's attachment to you but also on how familiar it is with its surroundings. Generally, it's recommended to keep doors and windows closed, especially for pet cats, as running away could lead to death due to not finding food. If the cat has only recently run away, immediately search the surrounding area. 
The reasons why the cat got lost are as follows:
1. You may have blocked the cat's way back, for example, by blocking the cat door or closing the security door.
2. He was arrested.
3. It means it has mated with another stray cat. So, generally speaking, if a cat hasn't returned home for two days, you should go out and look for it.
