Different sites have different policies for bolting, for example, Yosemite allows drilling and bolting, as long as it's done by hand (no motorised drills) [1].

Different sites have different policies for bolting, for example, Yosemite allows drilling and bolting, as long as it's done by hand (no motorised drills) [1]. Most bolts are placed by local climbers, and it's widely recognised that there is an "ethical" aspect to bolting: whether they should be fitted, where they should be fitted, etc. If someone came along and indiscriminately bolted a route, without any consultation with the local community, it would provoke an outcry. Generally, bolts are fitted by a climber on an abseil rope. They'll reach the top using an alternative, easy route (at many crags, you can reach the top simply by hiking along a path), then abseil down, and drill/fit the bolts whilst attached to an abseiling rope. Installing bolts whilst lead-climbing is done, but it's not very common. The climber would start by securing themselves to the cliff using traditional 'lead protection' (which is designed to be temporary, and generally not as secure as a bolt). Once secured, they would drill and fit the bolt. [1] https://www.nps.gov/yose/planyourvisit/bolting.htm https://www.nps.gov/yose/planyourvisit/bolting.htm