A colleague once asked me if older teachers were better than younger teachers. Well, I don't think I am in a position to say, I'm not an expect in that area. In terms of my personal preference, well I have this to say. What's the definition of old, what age range should be considered as old? I have no idea. Truth be told, I think referring to someone as old is kind of rude.
That being said, I think the so called younger teachers often lack the experience and wealth of knowledge of the "older" teachers. It comes with time, over several years of teaching. Some young teachers might have the knowledge but are not good at teaching. When "old" teachers teach, they do so citing examples based on their experience. Since they've been doing it for a while, and have seen several students come and go, I believe they know how best to transfer knowledge to their students. The argument that the younger teachers have "fresh" blood, hence are more knowledgeable with recent happenings isn't always true, in my opinion. I believe the "older" teachers are as up to date as their younger counterparts. They have a larger community of other teachers that they learn from, they have several research students that they work with and also learn from.
As I stated earlier, this is just my humble opinion.What do you think?