Old things in Thailand

When I walked to the toilets of the school in our village I was not very impressed by the quality and hygiene. But when taking a piss I saw the old toilets and I was very happy they were not in use anymore.

What reminded me of the fact that you see many times a new building (house / temple / bridge / toilets) with the old one still next to it.

Why? Too lazy to take the old one away? Or is there a cultural thing about not demolishing the old one?

So I am now thinking of trying to make a photo serie of old & new buildings together. I know at least 3 old bridges right next to the new bridge. No problem you would think? Well in 1 case the old bridge is half collapsed and you could still drive on to it. And sometime it will full collapse of course ... into the river and blocking the waterway.