I want to add some data, when user just login and remove this data, when he logout by himself or by the end of lifetime. Where is the script of checking lifetime situating? Joomla 3.8
Content plug-in does not have events for the user the events onUserAfterLogin you want to use can only be used in user, authentication or system plug-in try changing your plug-in to one of these types. Each different type of plug-in are used for different situations like system plug-in can be used for all events, but as you are performing some task on user events I will suggest you use User plug-in. Also, go through the different types of plug-in and events related to them.
Hope this helps.