Smaller, almost always.

We usually recommend starting with a small qualitative study and expanding only where the findings show that more digging will add value. Each phase stands on its own, so you get something usable at the end of the first round rather than waiting months for one large delivery.

The reason is not cost. It is that large upfront studies commit you to a set of questions before you know which ones matter. First rounds routinely change what the second round should ask. If you have scoped the whole programme in advance, you either follow a plan you no longer believe in, or you renegotiate.

There is a point where this flips. If you are making one large irreversible decision and you need to cover several distinct audiences properly, a bigger single study is the right call. That is rarer than it looks.