I don't know if jpolito got that schedule from, how shall we say it, a competing guitar instruction source or not. But the main instructor at this other site
came up with this exact same 30 minute suggested schedule. (It's probably blasphemy for me to say it but I got it from Learn and Master Guitar.)

It could have possible saved my guitar learning career. I was absolutely getting burned out on practice and really sick of pounding away at the practice. The concept of only 10 minutes of actual pounding and most of the rest of the time at actual fun completely revitalized me.

And I have to say that with only 10 minutes of actual practice instead of 45 or 60 at a time I really believe that I am progressing faster. It's all about attitude.

I have taken that 30 minutes and modified it for 45. So I go 5-20-15-5.

It's fun again!