I usually spend about 3 minutes previewing something like a 250 page book, and then I PR it. Razor has probably been doing this thing longer than I have, but I started getting spontaneous activation only a few days into the process. (Was practicing a lot.)
For some reason, after practicing A LOT, your brain feels, for a lack of a better word, tired. The more you do, the more you get used to it. So Razor is right, previewing is barely necessary. I used to spend about 10 minutes on it up until about a month ago. (That's 2 minutes past the recommended maximum of 8 minutes.)
