1. No questions during the brief
A good designer asks: who's the audience, who are the competitors, what's been tried already and why it didn't work, are there constraints (legal ones, for a government client, for instance). If a designer jumps straight to sketches after a vague "make it nice and modern," there's a good chance you'll get something generic that doesn't solve your specific problem.
2. Shows only one option
A single concept with no alternatives is either the designer saving time at your expense, or a lack of confidence in their own solution. Standard practice is 2–3 distinct directions, showing that different approaches were actually explored rather than going with the first idea that came to mind.
3. Can't explain why they chose that particular solution
"I just like it" is a weak answer for a business logo. Behind a good decision there's usually logic: why this font, why this color, how it relates to the audience and competitors. Without that reasoning, it's hard to tell if a solution was deliberate or just a guess.
4. Ignores feedback or argues instead of discussing
The difference between defending a decision professionally and ignoring feedback is willingness to explain and offer alternatives, rather than just insisting "I know better." A small amount of pushback is normal and even useful, but revisions should ultimately get addressed, not stonewalled.
5. No clarity on timelines, revisions or file handover before starting
If the answer to "how many revisions are included" or "what do I get at the end" is vague or irritated, that's a red flag before the project even starts. Terms should be clear upfront: timeline, number of revision rounds, what final files include, and how source files are handed over.