In my experience from Leopard till today, it is good to wait a bit, and if you can, format your machine. I've never run into problems this way. That said, this

In my experience from Leopard till today, it is good to wait a bit, and if you can, format your machine. I've never run into problems this way. That said, this might be the first time I upgrade rather than wipe because I'm not sure about its interactions with Homebrew