Flexlm Licensing-frequency of transactions

Arbotext CSDB for defence \ aerospace S1000D\S2000M

The version we have is 4.2 M39-4

Can you help me understand how the licensing works? Does the application get credentials just one time when the application is first opened, or are there repeated requests as each button is clicked, module opened.

I need an answer specific to our version.

The reason for asking is that weve experienced significant poor performance and wondering if there is an issue with the licence server response. Following a restart of the licence service performance improved dramatically..

Julian