If you are thinking of hiring a photographer in Barcelona, there are several things you should consider.
1. Specialization: It is not the same hiring a photographer specializing in architecture a photographer specializing in events. It is also true that there are many professional photographers with a versatile character and very capables of facing any kind of project with guarantees.
2. Budget: It is strogly recomnded that you ask for as many budgets as possible. Sometimes the cheapest become the expensive ones. My advice is to consider the more budgets the better.
Also the budget factor should not be the most important point determining which photographer you should hire.
3. Timing: Photo delivery dates. It is very important that you set pretty clear which date you need your job to be completed and share it with your professional photographers to stablish the most convenient date of delivery.
4. Contract: When the budget is very high, it is desirable to sign a contract to not let 'loose ends' between your project and the photographer you are hiring.
5. Copyrights and so on: Make clear with the photographer which are going to be his rights over the photos.
It is stablish by law that the photographer always have certain rights about his work. But if your project is very personal or very confidential, you can request the photographer to resign about his photo rights, always with an economic -or other kind of- compensation.
Oh I almost forgot! My name is Ricardo and I am a professional photographer in Barcelona. I invite you to take a look to my portfolio and if you like what you see, then contact me and we'll talk.
Have a nice day!