Hi Sachin,
In addition to what Shounak well said, if you want to keep your own records and not rely on the built-in log functionality, you can build your own.
As an idea, you can create a services application that will expose a service action that can be used across all the environment since the service actions don't create hard dependencies.
Just create a new entity with the information you need and then the log service action. Spread that action on the screens you want to audit.
This way you can keep the data as long as you can, you can even create a timer that runs from time to time and deletes records older than x time, this way you have a purge feature too and the maintenance is guaranteed.
Hope this helps
Best Regards,
Paulo Zacarias