I've heard/read some "experts" say a couple weeks, while other "experts" say (paraphrasing) jump right in--seemingly in equal numbers, so Brandon is probably close to the mark.
We're all going to have to learn how to "read" our BD's body language; might as well start from day one. Like your other pets, you'll spend some time trying to read/learn about each other for a while.
There are also plenty of articles & videos online, which have all their authors' own PsOV. While I was digging into this, I found some experts I thought were well-grounded, and some I thought were... well, a bit flakey (just like other pet "experts"). One article/video won't always tell the story, but after reading/viewing a few, I think you'll get a feel for whose information/opinions you trust.
