Chances are you picked that bad habit up from i OS programming, because it seems to be a common idiom.
If you’re writing a layer-backed or layer-hosting view on OSX, please implement the following NSView method: values.
If you have to deal with custom CALayers that host a collection of sublayers, you need to ensure that your CALayer is the delegate for its sublayers, and you can add the following method implementation: all the time, and you should be sure to update your layer’s contents image here, if required (As @rudyrichter pointed out).
I’m sure you’re smart enough to figure out what to do in your particular application…
I learned the above after some trial-and-error, and then spending some time reading this document. You should also be working with an external display attached to your Retina-enabled Mac (I use the Thunderbolt Display) if you’re serious about implementing support for high resolution displays on OS X properly.