One pair and a pair of pears

I went out to do the watering and to quietly admire the single pear on the 'cheeky face' cocktail pear, only to not see it. 'Damn... something got to it' I was thinking.  So I hunted around on the ground expecting to find a half-eaten (or worse, one bite out of it only) pear and there it was.  Whole, intact and not damaged from the fall.  So I guess it's ready.
It's meant to be a firm pear, with green skin and a red blush on one side.  Looks alright so far.  Haven't cut it yet but will. 

And these are the other two pears left on the other tree... slowly slowly.   My next question though is, how will I know when my Granny Smith apples are ready?  they're green with the white 'spot' through the green skin, just like you see on a Granny Smith apple... but how do I know they're ready?  It's not like you can check to see if they're soft, like peaches and things... anyone?