When I turned 40 my way of saying I wasn't getting old was by hiking to the top of Half Dome. I have made it to the top 17 times now. One simply needs to stand at the base of the cables and determine whether or not you are ready and able to make that 900 foot climb. My first 10 or so climbs to the top were quite uneventful but pleasant. I could set my pace, rest when I needed, even take some pictures on the way up or down. Those days don't exsit anymore unless I am at the cables early in the morning or late in the afternoon. The crowds have taken the fun away from the experience, and have made it a much more dangerous adventure. Families with children, indivuduals who get up there, etc, crowd the cables to a point where you can only move as the endless line of people move. Thus, when a child or someone else get scared and stops moving, everyone behind or above them also stops moving. On summer days, that literally can man up to a hundred of us stuck where we are until things move again. I have taken as litele as 30 minutes to get to the top, or as long as 1 1/2 hours.When the traffic stops on the cables, some brave folks go outside the cables to get up or down more quickly (including me) increasing the risk factor. I have never seen anyone clip on to the cables, not that one couldn't do it that way. However, if you need to do use that type of protection, it would slow the entire line up as you would need to clip and unclip numerous times where the cables a splice together and where the support poles are located, about 20 or so feet apart, all the way to the top. For me, I have found that unless you do Half Dome in the early or late season, or at night, the fun and experience is no longer there. Be safe, and enjoy the great outdoors!
Bobd