Say you have a lot of files to produce that are basically the same. Lets say it's a series of blister packs that are all pretty much the same - the logo, the product name, background image, price, some small print, manufacturer details, barcode etc. and most of these will stay the same across the whole range with just things like the product name, price and barcode changing from pack to pack.
A perfect candidate for InDesign and a master page yes? But unfortunately you have to do this in Illustrator, either because the client insists, because you're not comfortable in InDesign or perhaps you have inherited old artwork in Illustrator format that just needs updating.
Well here's the trick. Did you know that you can place an Illustrator file into an Illustrator file? So what you do is set up your file to the correct dimensions but with only the elements that are common to every pack - the MASTER elements, i.e. The background, the logo, background image, small print etc. and save it as a plain Illustrator file. Lets call this the master illustrator file.
Next you set up your Artwork file to the same dimensions and PLACE the master illustrator file into it, on its own layer. Now you can add the variable elements like the product name and price on a layer above till everything looks just right. Now you have one pack all set up you just need to create additional artboards for all the other packs in the range and copy and PASTE IN PLACE the elements you have created onto each artboard and rename each product, price etc. across the range.
Here's the beauty of this though. If subsequently the manufacturers address, the small print or anything else on the master layer needs to change, you just open your original master illustrator file, make the changes and hit save. Then back in your artwork you simply update the links and voila. those changes have been made to every pack.