Chantal sent me an email querying about eliminating shampoo and conditioner completely in favour of occassional use of water and a hair brush to help oil travel down the shaft. This is the 'water only' method.
The idea originates from a British woman who says that she has not washed her hair with shampoo or conditioner for 11 years (that was in 2005). She does by all accounts appear to have pretty decent hair (naturally straight hair).
1. Could this work for you? If you can dry brush or dry comb your hair and use no styling aids possibly. The brush appears essential to removal of dirt. However if your hair tends to break or tangle when handled dry don't try it.
2. Is this method more gentle or less damaging? I would guess no and perhaps even guess it may be more damaging for two reasons. First, when hair is shaken in water alone, some protein is lost (i.e damage). Some surfactants in shampoo appear to inflict less damage than water (jog your memory here). Secondly, using conditioner makes hair easier to comb (the oh so desired slip which lets the comb glide through) so I'm not entirely convinced that leaving it out during the combing process is better (jog your memory here and here).
3. Is this method effective to clean hair? It may be for some depending on where you live/work (environmental pollution = dirt on hair) and how oily your hair is. There are certainly devotees over at long hair community.
Unfortunately my search engine is givng me trouble today and won't let me access journals, I will definitely update if I find some interesting science to match. Are you curious, would you try it?