Trip conditions should be straighforward. These are whatever is necessary to cause the relay to require a TRIP.
However, there may be circumstances where you need to 'latch' the output to 'sustain' a trip until other requirements are met.
Maybe you want to wait until a motor operator opens a switch, then a limit switch contact in the switch control reports back that the switch is open (although this might be handled better by 'seal in' logic in the motor circuit). Once the switch contact reports 'open', you can 'stop tripping'.
Maybe you have an old external reclosing relay that has to go through a timed logic cycle after the 1st relay sends a 'trip', etc.
A lot of SCADA systems only like to send a short term (~0.5s) control output, and you may need to 'seal in' the relay's trip function for a longer period. Establishing necessary conditions for the trip signal to drop out may be more trustworthy than relying on a simple timer and assuming whatever it is has finished.