Don't be afraid to ask for either the original files or a .svg (scaleable vector graphic) file. If you ever want to have the design incorporated into printed materials, you will need these files as they will allow another designer to rework the files in case the original designer goes out of business or does not offer these services.
Ask if You Don't Know
A lot of banners are made in Photoshop or similar image editing software. They're wonderful for creating images for the web, but not always for print. The reason for this is the difference between bitmap images and vector graphics, which is a whole separate topic, but basically the difference is bitmap images become pixellated if resized too much, vector graphics retain their clarity. Also, drop shadows, gradients and special effects done in these programs don't always print out the best quality either.
Another thing to keep in mind is that print colors are not always the same as what you see on your computer. Computer screens, web and printers all have different gamuts for color. Which basically means the entire range of colors available on a particular device such as a monitor or printer. A monitor, which displays RGB signals, typically has a greater color gamut than a printer, which uses CMYK inks. When a color is "out of gamut," it cannot be properly converted to the target device; for example, to a different type of printer. So the colors may vary slightly on your printed items.
Keeping your look uniform will help your business 'brand'. If you have a banner that has one design, a business card with another design and stickers with yet another design, you may be sending the wrong signal to your customers. Coming up with a look that is unique to you is another step in marketing yourself as a business and not just a hobby.
Thanks for stopping by!