I wear a size 10, possibly might get a...
I wear a size 10, possibly might get a 10.5 boot this year. Should i go with the large or medium bindings?
You should go with the medium bindings. Most boots are built on a size smaller platform, so it is a size smaller anyway. The medium bindings will fit boots 8-10, the 10.5 is the cut off between a medium and a large. If you new boots are bulky then go with the large, but I think the mediums will be great.
Sizing will really depend on what brand and model boot you have. I have a DC allegence size 11 and use a Large in the missions. best thing to do is take a boot and test fit them at a local store, or order both sizes from dogfunk and return the one that doesn't fit.