Fast cavalry and free reform

Unless it charges, a fast cavalry unit is allowed to reform as many times as it wishes during its move, even if it marches, PROVIDED THAT NO MODEL ENDS UP MOVING A NUMBER OF INCHES HIGHER THAN DOUBLE ITS MOVEMENT VALUE.

Not sure what this really means does this indicate that free reform is counted as a move? So if you free reform 180. How much movement does it use up, if any. Not sure if I understand what this rule means

It means they can reform their ranks and files as many times as they want while moving.  It makes them highly agile on the field because a unit of 10 fast cav can start 5x2, move up 8" and then reform into a conga-line to get past a small gap between 2 unit or whatever, and then move another few inches and reform into a 5x2 formation once again and finish the rest of their move all in the same movement phase.

Marauders on horses are nasty like this.

So basically they can march 16" with unlimited reforms.

Just the way it is worded indicated it costed a little movement to make a conga line then back to standard formation

I'm not 100% sure anyone has answered the subtlety of Isa's question. Do the reforms count as part of the overall move? Do you need to measure the distance of every model in every reform deducted from their total movement? It makes fast cav a LOT less fast if they have to account for every reform made.

The answer is that while the RAW is up for debate (both sides can be argued convincingly from the text), it's pretty clear what it works like in practice. The reforms are essentially free and it's the final displacement along the direction of the unit's move that matters. Essentially as long as no model ends up more than 2xM when marching, you're good. This is simply a matter of playability. A friend brought this up and the net conclusion was unless you really want to individually name each of my 12 seekers in my unit and watch while I take 30 min moving the unit with a spreadsheet tracking the movement of each model - yeah, I'll just move them their move and assume all relevant reforms don't count to the final movement.

It means exactly that. You can reform as many times as you wish, subject to the normal rules for reforming.

It is for example for the following situation.
-----
Every dash is a fast cavalry model.
After a reform you get
                             IIIII
Now if you would move the most right model 16" then the most left one would have moved over 16" so you can't move as far as you would want to.
That is what the rule implies

Ok how about for the context of a hex wraith can the essentially march 16" through a unit reform and face the back of said unit and charge the rear the following phase

Yep, hexwraiths can do that.

-Snark

Thanks for clearing all that up. I love it how everything in the brb is so straight forward and can not be argued or misinterpreted in anyway, makes for learning this game all the more easier 

In the move to conga line through a gap just imagine an old western movie were the people on horseback would slow down a little and let the leaders squeeze through the gap first and than speed up to catch up to the leaders and assume the formation. or basically pick one model in the front middle and measure his movement.

I've always understood it that the only important thing is that each model is not more than double its movement distance from its starting point, at the end of the movement phase..   

So the function of this rule is to prevent someone from reforming the unit in such a way that the unit is shifted forward, and then the unit is moved forward the maximum distance, and then reformed again to gain some extra distance.