When setting the autogrow properties for a SQL Server data file, is it better to use a fixed size or a percentage growth?

It's hard to say always or never in the performance-tuning world. It's usually better to define the reasons why certain decisions are better in particular situations. Whether you use a fixed size or a percentage for autogrow settings, you'll still have to tweak the values as your file grows. Typically, I'll set the file size to a reasonable starting point, t...