What is the benefit of multiple string wraps around the tuning posts?
Almost all guitarists wrap 2 - 3 winds around the tuning posts, yet it has been well established that this makes stretching the strings in (especially on a floyd brige) take longer as the winds take more time to settle than the length of string over the fretboard.
Some years ago I stopped winding as much string as I could around the posts (I pull them through as tight as possible) and I haven't observed any loss of tone, tuning stability or increased string breakage.
However, is there any documented benefit for using multiple winds or does everyone just do it out of habit?
I have never heard about any benefit for using multiple wraps.
I wrap the strings about 2, 3 winds max on my guitar without a whammy bar and haven't had any problems with that.
I noticed that generally the higher strings require some extra winding in order to prevent them from sliding through the holes in the tuning posts. While the lower strings stay completely stable with just a couple of winds.
Once I had a 'Flight' guitar with a synchronized vibrato system like on Fender strats, 2 - 3 winds was enough with that guitar too.
I have just checked my new Ibanez GRG270b guitar with the floating bridge, it still has the strings that were installed by the manufacturer, there are 3 winds for the lower strings and 5-7 for the higher ones.
I think it's useful to spend extra time on putting some guitar lubricant in the grooves, at places where the strings pass through (such as in the nut, the bridge...), it will greatly improve tuning stability and decrease the chances of string breakage.