I hear people suggesting I should have at-least 30FPS in the game to have a satisfactory experience, I wonder, how do I enable FPS monitoring in a gameplay?
Fraps is a Windows program that allows you to monitor the frame rate of any game "utilizing DirectX or OpenGL graphic technology". It also allows you to easily take screenshots and videos of your gameplay. There's a perfectly functional free version, but it only supports 30 second videos, has a small watermark, and screenshots are in the .bmp format.
Some games can display the current FPS if you enable the right setting. It might even be a console command.
30FPS is still quite low. It would be worth trying higher rates to see what you prefer. Some people prefer really high FPS and low resolution while others are exactly the opposite. It's very subjective and so worth experimenting to see what works for you.
In America's Army it is possible to view the current frame rate by entering stat fps into the console. Perhaps this works for other games using the Unreal engine too.
You will notice how your frame rate depends on the current environment. In some areas you will perhaps get 60-70fps (usually inside buildings) while in large outdoor environments it will drop to 25-35fps.