2 hours is a good estimate for the average person. My fastest time is 50min up and back and I think the fastest time ever is 15minites (only going up). However, it's not uncommon for people to take 3 hours either, especially if they are just out to enjoy the nice weather.
It depends of how physically prepared you are. The trail changes drastically it level and some areas are very steep and you need to slow down. Plus since it is one of the most visited places to see the sunrise ,it always is crowded . So please go early and take lots of water with you. If you scared of heights avoid going since some area you have to basically climb on the edge of the cliff. It back and forward without stop will take you probably 2 hours, but what's the point of going there and not staying to enjoy the view.
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