I check out the supplied bump map with a texture and see if it's been done correctly. Most aren't. Seriously... about 99.99% are just so obviously the colour texture turned into a grayscale image. Human texture makers: PLEASE DON'T DO THIS! It is seriously bad because, for example, on a face it will make dark eyebrows appear to sink into the face rather than stand out, moles will not be raised but will be cavities, and so on.

The EZSkin procedural is quite good in most cases, and the best would be to take a blend of the procedural and a properly-made bump texture.