I very much support the sentiment of Big Piston's post. I'm not here to slag anyone, but I simply believe that as altruistic as it may seem, a 90 hour, 150 hour, or 250 hour pilot is very unlikely to have the total flying
experience themselves to comprehensively train another person to fly. I agree that it would be possible with a very broad array of flying types and circumstances, that 250 hour pilot might have adequate experience to begin elements of a student's training, but that
experience is not obtained "hour building" around the circuit or local flying area in 250 hours.
I could care less what the description of the license is (PPL vs CPL etc.) it's the flying experience which makes the pilot. I held a PPL with great pride, until with about 5900 hours, it wa necessary for me to obtain a CPL. The ground school challenged me (things had changed in 31 years) the flying portion was not the least bit challenging, and was completed in the shortest possible time as dictated by the examiner. I would think so, as I took my flight test in the aircraft I have owned for 24 years!
When I had 500 hours, I thought I knew it all. When I had a 1000 hours, I realized that I had a lot more to learn about flying. Now, with more than six times that, I wonder if I will ever really be the good pilot I aspire to be. The examiner though I was worth a whole page of 4's though
My personal and overly hard nosed opinion is that "hour building" your way to the minimums, to then go and teach flying, is just not what any student deserves. Yes there are things you could teach adequately, but a whole lot more experience is due the student. That said, apparently the regulators have identified the minimum experience requirement by a number of hours. I have to "accept" their wisdom, but I don't have to agree....