Relay coil set and reset with momentary switch
Set and reset times are the time needed by the relay to physically move, and stabilize the latch. (It might be bouncing around a bit before settling)
A rule of thumb is to energize the coil for 5x this time, to be sure that even an aged/hot/cold relay is able to switch states. Note 2 states this: Use a minimum pulse of 100ms.
That being said, unless you are continuously switching, or operating the relay very frequently, there should be no issues energizing the coil for several seconds without damage.