Clear communication and expectations between partners is a vital aspect of safety when climbing. This can become critically important if voice communication is limited by a long pitch, wind, route going out of sight, or other Less Than Ideal (LTI) circumstances.
Spend some time at the beginner routes at your local climbing area, and you’re bound to hear some conversations like the following:
Excited newbie leader, reaching the anchors on a one pitch sport climb: “Yeah! Wooo! Phew! Belay off!”
Attentive belayer from below: “Are you sure about that? Don’t you want to clip the anchor and lower off?”
Newbie leader: “Oh, hmmm, yeah, right, okay, better keep me on belay. Ready to take? You got me, right?”
Yes, this is a potentially lethal mistake narrowly averted by an attentive belayer. It has happened: distracted leader calls “Belay Off”, their partner obeys, the leader clips the rope into the anchor and thinks they’re going to be lowered, leans back on the rope, and falls to the ground. Yes, awful. And easily averted by about a 10 second conversation on the ground before anybody starts climbing.
There are four different things that a leader can do when they reach the top of a pitch.
(For this discussion, let’s leave out big wall climbing, where the leader would usually fix the rope for the second to ascend.)
belay their partner up to their position
Before the leader heads up, take a moment on the ground (hence the name) to confirm which one of these four things is going to happen.
Sometimes you can easily eliminate one or several of the options. Is there no way to walk off the route? Well, let’s skip that one. Have you already agreed on a multi pitch climb, and for sure the second is going to come up? Well, then that’s pretty settled as well.
But even a standard one pitch route has some choices to make. The most important one is probably if the last person at the route is going to rappel or be lowered, with lowering usually the preferred option.
Whatever the possibilities, you should have complete agreement as to what's going to happen while on the ground, and not yelling at each other back-and-forth on the cliff.
Now, you can of course change the ground plan later on if for some compelling reason you need to, just to be sure that this change is also clearly communicated to your partner.