If the rock is good quality, then you can get away with placing the bolts a little closer together, which makes the route much more accessible to climbers who want to push their grade without having to “donate” a bail biner to the crag.
You can also solve the ever-complained about “problem” of the first bolt being set too high on routes, to counteract unexpected ground falls while clipped in.
You see, those ground falls resulting from poor bolt placement happen when the distance from the ground to the first bolt is not further than second bolt is from the first.
Sounds complicated, but the easy way to solve it is to just place the second bolt closer to the first. That lets you place the first one low enough to enjoy “not breaking your ankles if you fall before you clip into the first bolt.”
For a rule of thumb, you’ll want to place bolt number two about half the distance that bolt one is from the floor, with bolt three being no further from bolt two than bolt one is from the floor.
For example, you could place a low first bolt at 8 feet, then a half-distance second bolt at 12 feet, and a third one at a maximum height of 20 feet from the ground. After that, you can place them every 10 to 15 feet, according to rock quality and your own preference.
Alternatively, you can just opt for a high first bolt at around 15 foot. In this case, the rule of thumb still applies: have the second bolt half that distance, and the third no more than that distance.
The advantage of the high first bolt is that bolt three can be at 37.5 feet, while with a low first bolt it’ll be at 20 feet. That’s why high first bolts are so common in some areas. You get almost twice the distance covered with the first three bolts. Though, of course, the downside is that you need a stick clip to clip the high first bolt if you don’t want to break your ankles.
With all this considered, each pack of 10 bolt hangers is ideal for setting one less-than 30m sport climbing route fit for a standard 60m climbing rope. 8 bolts, with two at the top of the route to create an equalized anchor from.