SQL Server has the ability to store the current execution plan, but the next version of SQL Server also promises a new feature that also stores the history of a particular query plan. This should be helpful in solving performance problems related to changes in execution plans. This new feature, called the Query Store, can help you with troubleshoot performance problems related to plan changes. It will be available soon on SQL Azure and on the 2016 version of SQL Server. It is expected to be available on the Enterprise Edition of SQL Server 2016, but it is still not yet known if it will be available on other versions like Standard Express editions.
During your troubleshooting you might discover a database query is slow, but the next problem is understanding why a query is slow. Not every query problem is related to plan changes, but the Query Store can help you understand if the plan has changed.
There is a great video from Microsoft that will show you some additional aspects of this new feature.