Hi I'm getting 2 leopard tortoise's tonight with the whole setup, I know they are being kept on wood chip at the moment. Do I change it tonight to coco coir or wait a few days for them to settle in ?
I wouldn't use coco coir for a leopard. I would use orchid bark. Its cheaper too.
When you change the substrate isn't critical. A few days won't matter and dealing with one big change at a time might make things a little easier on them.
On the other hand, if it needs to be changed because its old and soiled, I don't think its that big of a deal.