What is an overview of beliefs on how one can become demon-possessed?

The possibility that a person can become demon-possessed is a well established fact of Scripture. The four gospels as well as the book of Acts make many references to individuals who were tormented and possessed by evil spirits. But what about the *how*? What would be an **overview** of beliefs on *how* people can become demon-possessed in the first place? Can evil spirits enter and possess whomever they want (and to what extent, are there different degrees of possession)? Are there spiritual laws that determine when, where, why, how and the extent to which a person can be influenced and ultimately possessed by evil spirits? ________ Related: - https://christianity.stackexchange.com/q/81001/50422 - https://christianity.stackexchange.com/q/84082/50422 - https://christianity.stackexchange.com/q/84365/50422 - https://christianity.stackexchange.com/q/82874/50422