>Everything in ADO.NET uses a DataReader. If, for example, you fill a dataset from SQLServer then a SQLDataReader is used behind the scenes.

Since the debut I have been using .NET, I open my SQL Server connection in the Application.Initialize() method and refer to it as many times as I need. This avoids opening and closing the connection for everything request. This is why it is so fast. I do the same thing either for a desktop application or a Web application. On millions of hits and SQL Server requests, I got that one about 4 times in a year.

So, is it an assumption that always using the same connection could create this situation after hundreds of thousands of SQL requests? If yes, if I open and close the connection for every SQL request, this will slow down the entire application.