What you need from a designer...
This is a problem I encounter all the time in small business. They have got someone to design their logo but never get the correct format and original files! Here is a list of what you need and why...
Always ask for the original files because if you decide to use a different designer he is going to have to start from scratch and your logo will never be exactly the same. It is also good to have this incase you want to make some changes to your logo.
Secondly, Make sure you get every variation in PDF format. PDF keeps the file in it's original form and keeps the colours correct. Most printed prefer to have your logo in PDF format.
Now days it is also becoming more and more important to be on the internet and using social networks, so ask your designer for something in JPEG format. Important to not here is that colours on a computer always look different to print. Try get your designed to make a web logo that matches the colour print.
Lastly and most importantly, ALWAYS get the designer to give you a break down of your logo. Ask for the font that was used and the exact colour. When is comes to colour either get the Pantone colour or the CMYK as these are best for printers and keep the colours correct. An RGB version is okay but not ideal.
These things might seem minor to you now but they will save a lot of time and money later on. If you aren't to sure what to do get someone who understands and ask the to get the right information.