The case against a full brand book early on
At the earliest stage a startup changes fast: positioning, audience, sometimes even the product — all of that can shift meaningfully after the first few months on the market. Putting money into a detailed brand book with patterns and tone-of-voice rules at this stage is risky — there's a real chance the brand needs rethinking in six months, and the money ends up spent on a document nobody uses.
What's actually needed early on
A logo that works across formats (not just on white), a basic color palette and a couple of fonts — that's enough to make a pitch deck, a website and social look like one brand. This can be packaged as a minimal guideline a few pages long, not a full brand book.
When a startup needs it sooner rather than later
There are exceptions. If a startup is raising money and pitching investors, a brand book — even a small one — signals that the team thinks in years, not just the next sprint. If more than one person is already touching the visuals — a marketer doing social, a developer building the landing page — minimal rules matter early, or the visuals start drifting from month one.
What I usually suggest
For startups it usually makes more sense to order a logo and a compact guideline, and save the full brand book for after product-market fit and positioning have settled. That saves budget exactly when it matters most, without sacrificing a professional look from day one.