Query Execution History logs every SQL statement that you run in a file on your disk or in a table in a database you specify with a connection string. This way, if you're working on some script you can get the full history of every change you've made. SQL Statements are saved in a list that is written to a file and/or a database with a timer which you can set to a desired interval. Older query history logs can be auto deleted. Time after which the logs are deleted is user settable. The size of the code to be saved can also be set up to the maximum of 5 MB of code.
Version 5.2 adds exclusion keyword to not save a query in SQL history. The keyword is a preset comment and has to be at the start of the executing selection.
Version 5.5 adds query duration data. Duration is measured strictly from SSMS client side and does not touch the server. Query duration is saved only for local file-based SQL History. Searching also supports filtering on the duration.

Tab Sessions make your work with tabs even easier. Each tab is saved periodically as defined by the interval for Window Content History. The two features are connected. You can also Restore Last Session by pressing the button on toolbar. This openes the last saved tabs already connected to the server they were connected to before. Since version 4.9.5.0 the window's pinned status is also preserved. Simple, easy and fast.

Window Content History saves the whole text in all opened SQL windows every N minutes. The default being 1 minute. This feature fixes the shorcoming of the Query Execution History which is saved only when the query is run. If you're working on a large script and never execute it the existing Query Execution History wouldn't save it. By contrast the Window Content History saves everything in a .sql file so you can even open it in your SSMS. The Query Execution History and Window Content History files are correlated by the same directory and file name so when you search through the Query Execution History you get to see the whole saved Window Content History for that query. It is turned ON by default.

Current window history is a dockable window that shows queries executed in a currently active window. It alse has a search box at the top that filters results as you type. Each entry also shows the color of the server/database it was run on. This is very helpful if you change your connection in the same query window.