Google Analytics by default starts a new session after 30 minutes of inactivity, but your experience says its too much or too less. Can you change it? Sure you can. Navigate to Admin >> Property >> Tracking info >> Session Settings and change the settings for analytics session.
The same way you can also change attribution logic for google analytics. By default Google Analytics keeps attribution of campaign for 180 days unless overridden by another campaign. You want to make it shorter or longer? You can do so by navigating to the same path as above.
Starting career with paid search, Nikhil has built and managed award winning digital campaigns, has been Google Adwords Top Contributor, Planned and implemented several complex and large scale web and mobile analytics implementations. Currently working for Myntra as Manager Analytics Nikhil is also conducts trainings on Web Analytics, Mobile Analytics and Digital Marketing.