How much budget for brand vs. performance marketing?

In the early years roughly 70-80% performance and the rest brand; for an established company the split moves towards half and half. Performance brings revenue now, brand makes that revenue cheaper later - which is why you never run only one of them.

Run performance alone and your cost per customer creeps up every year, because you pay for each individual moment of attention. Run brand alone and you'll be well known and broke, because awareness doesn't pay wages. Stage decides the ratio: a young company first has to prove someone wants the product, and performance tells you that fastest. An established company gains most from being remembered before the search even starts.