Is it advisable to enable Man-in-the-middle protection all the time?

[helpme]

While using the device manager, I encountered this line;

#define SEC_PARAM_MITM 1 /**< Man In The Middle protection not required. */

Since security is important, is it advisable to enable Man In The Middle protection all the time? When would be situations when disabling this protection is better?

I am using nRF-DK hardware with SDK_11 and s130.

[Petter Myhre]

Security can be important. It depends on the application. What kind of security do you need?