"Likewise the Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit himself intercedes for us with groaning's too deep for words." Rom 8:26.
Intercessors don't necessary pray for a long time, but are prompted what to pray for. It is not about the length of time but about the prompting: "I must pray for this." It expands the bounders of the world in which we live. Responding to the Spirit's prompting. The Hebrew word for intersession "paga" (מָּגַע) has three meanings in the old testament:
To happen or light upon by chance or circumstance (Gen 28:10-17). Found a place to stop and rest because of night fall. The Lord was in that place and Jacob didn't know it.
To fall upon in attack (1 Sam 22:1-19) Strike the Priest. Saul order his guards to attack his enemy on command, not by their choice.
Boundary (Josh 19). Same word for Intersession can also be interpreted as "boundary". Pray whenever the bounders of the Lord are encroached upon. We should pray for those who have stepped outside the boundaries.