I think daily Renkos are really good for swing traders who can't babysit a position during the day. They also enforce discipline when trading, which I lack. I also really like the fact that they essentially conceal the small scale price movements that obsess so many of us.

In a less volatile market, weekly Renkos may also be useful. For instance, this weekly Renko of the SPXtells the whole darn story!

In TA less is often more. I've also been playing around with charts like this onewhich de-emphasise price in favor of indicators such as MACD. 

The time axis on a Renko chart doesn't have a fixed scale. The scale changes as the rate of change of the SP changes. So you just have to read off the dates at the bottom. This chart covers July/August. Basically, when the boxes are red you go long XLF and when they are white you go long SKF, but you wait until the parabolic SAR flips to make the trade. This avoids most whipsaws. 

I know there was some discussion of Renkos a while back but I think they are very useful for keeping a position which is agnostic as to whether we are in a bear or a bull market, and which enforces tight stop losses, while also keeping the number of trades down to a minimum.

Ideally I think you would have several of these systems trading on paired bull/bear ETFs which are as orthogonal to each other as possible (ie they don't all go up and down in sync). I'll try to post more of this stuff as I work through it. It's all about choosing the parameters just right!