The best time to begin incorporating identity strategy into the mix is when the vision for the product is clear. If you can clearly articulate what you are building, the key features, the environment you are attempting to create, and who your target customers are, you're ready.

Here's the good news—quality brand and identity advice and visual design does not have to be very expensive. I've worked with large agencies and freelance experts in the past, and the only difference I have experienced is the cost.

Wishing you much success!