User Activity list - back end

On the back end, I can click on Users, then a specific user name, then on the Activities tab to see a user's recent activities. Right now, I have only had the site up for 3 days, running tests, so I only see 3 days of activity. Will this list continue to show me all of a user's activity, or at some point will it start to show me just the last few days or weeks or some subset? I would VERY much like to be able to see all of a user's activity, from when they register until the current date, on this page. If it does not do that automatically, what do I need to change?