1. Generally speaking, the duration of the relationship should be at least six months to a year, and both parties should have a relatively deep understanding and adaptation process before deciding to get married, which is usually not considered a flash marriage.
2. The definition of flash marriage often focuses more on both parties quickly deciding and completing marriage registration within a short period of time (such as a few months), lacking sufficient mutual understanding and adaptation process.
3. The important thing is that there is no fixed time standard for how long a flash marriage should last. It depends on the development of the relationship between the two people, the degree of mutual understanding, and the individual's preparation for marriage.