Should I expand the appearance of my gradients before printing?
I know that I should create outlines on all the text I'm using before printing to ensure that any unique typefaces get printed correctly, and I see that there are options to also expand gradient appearances.
Should I be expanding these before printing?
What advantages would this have if any?
Actually, you should avoid expanding appearance, converting fonts to curves, flattening transparency, etc, unless your printer (the people not a device) specifically asks you to.
Those kind of things are hold overs from many years ago. A lot of print shops are still stuck in those days, but the reality is times have changed.
Having said that, we used to ask for expanded gradients, etc because it standardized the files we would receive. We knew what to expect, and what our RIP software could and could not handle. These techniques eliminated a lot of the variables that could show up in production.
On the other hand, we got files that could not easily me modified (for instance, try altering a flattened Illustrator file) and other issues.
In general, no.
I wanted to point out that it is better to supply a PDF (PDFX/1-a) for print production than an actual Illustrator file. PDFs are more than capable of embedding fonts (if the license permits) and maintaining all the appearance aspects of any Illustrator file, then outputting that correctly. PDFX/1-a is a press standard that has been around for more than a decade and is pretty much fool-proof if provided.
If you expand gradients within Illustrator you end up with one of two things.... A) a clipping mask which masks a raster image, or B) a gradient mesh which mimics the original gradient as closely as possible. [A] is bound by traditional raster limitations and can easily result in a poor appearance if the file is not handled correctly. [B] is not always accurate. The automated conversion from a gradient to a gradient mesh can, at time, result in a different gradient. And you end up with a mesh which can be more complex than a standard linear or radial gradient.
By leaving gradients in tact within an Illustrator file you provide the versatility of ensuring the gradient is output at the optimum resolution of the output device (the same as all vector data).