Look at the thinking, not the artwork
Every studio portfolio looks good. That is the point of a portfolio. What separates one from another is whether they can explain why a piece of work looks the way it does, and what problem it was built to solve. Ask about a project you like and listen for whether the answer is about the client's business or about the designer's taste.
Ask who actually does the work
It is common for the person who pitches to be different from the person who designs. That is not automatically a problem, but you should know before you commit. Ask who will be on your project day to day, and whether any of it is being passed to freelancers.
Find out what happens after handover
A brand that nobody can apply falls apart within a year. Ask what you receive at the end: guidelines, working files, fonts and their licences, and how much support you get while your own team learns to use them.
Check how they handle disagreement
You will not love every concept, and a studio worth hiring will expect that. What matters is whether feedback leads to a better second round or to a defensive conversation. Ask a previous client how the studio responded when something was not working.
