I'd replace the boots. Bindings will outlive a pair of boots, so my thinking is to replace the item that has the shortest lifespan.
Now, if your boots fit well and are fairly new, I might replace the bindings instead since bindings have decent resell value while boots have virtually zero resell value.
"People say that marijuana smoking is going to get in the way of my career. I say to them that on the contrary, my fighting career is getting in the way of my marijuana smoking." -Nick Diaz