For a Dayton install we start with the opening itself - width, height, headroom, and backroom, since newer construction sometimes has less backroom clearance than older garages built with more generous framing. We size the track and spring system to the actual door weight, not a generic chart, because a lot of the doors that get installed wrong are oversized or undersized for the opener already on the wall.
We also talk through insulation and R-value honestly. Given the climate here, a double-wall steel door with real foam fill is worth the upcharge over a single-skin door, especially if the garage shares a wall with living space. We won't push the top-end door if the opening and usage don't call for it - sometimes a mid-grade door is the right call and we'll say so.