[LunarBerry]

Personally, I and all my family have always allowed "free-feeding" with all the dogs we've had. We may, of course, give them more than they should (wet/canned foods and treats, etc.) ^^;; manually speaking. But otherwise they have been good about eating when they need to from the dry kibble we leave out all the time.
My Kimchi, current yorkie, might sometimes need a bit of an incentive but for the most part does well on free feed (she's just lazy and spoiled at times). Maybe my household has been different or lucky, but it didn't matter of the age of our furbabies. But I will say this, when food is being set out in a scheduled manner they'll likely to eat it even when not really hungry. My personal feeling, limiting them food encourages the feast/famine instinct and they'll react to normal food the same as treats, in some cases that's not bad but in general, it'll encourage over-eating. Of course, that's different with each canine as they have their own personality and limits.
We've always had good eating habits when it's just the basic "kibble" (even when changing to a premium quality and they eat that more, they'll have more discipline eating with the daily kibble), it's when we get into other foods/treats that it becomes an issue.