Newbie: Please help me to understand ES

OK so I am really new to ES and am having trouble understanding, what I think, are some key points.

So I understand that the write side receives commands, then the Domain model processes the command, updates the state in the Domain model and generates events that are send to the event store to be persisted.

What I want to know is for how long is the domain model ‘alive’, is it setup for each request and then discarded. Is it available to only the current users session.

I would start with setting it up for each command. Then discarding it. You can optimize later.