When you are setting up a new SQL Server machine you need to determine how big you should make tempdb. To make sure you size tempdb appropriately you should monitor the tempdb space usage. If there are autogrowth events occurring after you have recycled SQL Server than you might want to increase the size of your tempdb data files. If tempdb never uses most of the tempdb space, then you might want to consider decreasing the size of tempdb.
Have you ever checked the size of the SQL Server tempdb after restarting SQL Server to find that it's reset? Simon Liew explains this behaviour.