For emerging fund managers, it's advisable to approach potential anchor investors only after having a minimum of 10%+ of your fund hard circled in PACTs. Engaging with anchors too early can delay closings and complicate the process. It's crucial to prioritize those who can commit to your first closing promptly.
TL'DR - Never. Anchor investors are no longer common for emerging managers, especially, in Fund 1s, and they are becoming obsolete in general. Anchors are a way of the past. In modern fundraising, emerging managers rarely have an anchor, especially in Fund 1.