I have a php website connected to mysql.

Everypage that runs a query first has the connection line:

$db = mysql_connect("localhost", "root","");
mysql_select_db("logbook",$db);
(PS - don't worry, it's running on webserver localhost port 80 closed to public)

Anyway, when do i need to close the mysql connection?
The user would maneuver around these pages....
Should i have a mysql_closec -> when he/she loggs off the website?
Why do i need to close the connection? What are the benifits?

thanks
Noam

If you don't use persistent connection, the connection is automatically closed at script end.