Let me say this again: for most people and for most situationsthe time/temperature method of development is much easier and more accurate. Development by inspection requires a good deal of experience to get it right. I know that it has a certain mystique for some people but that in itself is not a sufficient reason to use it. I used it many years ago when light meters were an uncommon luxury. I would have preferred not to.
This is very good advice. I have only developed by inspection about twice for the experience of doing so and can't think of a situation where I would need to do this again.
I would like to add that in order to use this method the eye must be fully adapted to the dark. For the average individual this is about 30 min of sitting in the dark before one can start. This can be incredibly boring. Some good music helps but still I would prefer to be doing something else.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.