If you prefer to have a professional document that features color and graphics that come to the edge of the paper, then you need bleed. I don’t know anyone who wouldn’t want something professional. As you can see from the attached image, bleed (red line) goes beyond the trim of a page (black line). This additional info gives a professional printer space to trim when completing the finishing on a document. The margin is a good safe area to ensure none of your text or other vital stuff gets cut off.
When setting up a document, the standard bleed amount is an additional 1/8″ on all sides. Page layout programs have this option available when creating a new document. But, in the case of other “publishing” programs like MS Word, a work-around is achieved by setting up the whole document with bleed added to the size. So, instead of creating a letter-sized flyer at 8.5″x11″, the size would be 8.75″x11.25″.
If there is no bleed, and the color goes to the edge of the paper, there is the possibility that a thin white line would run the edge of the page after it’s trimmed. Human error can cause a number of factors. The print can be off a hair or the cutting machine might be having a bad day. This is why bleed is important. It’s like insurance for your work. Professional print shops will require bleed unless you don’t have graphics go beyond the margin to the edge of the paper. And if you let them create the bleed in your original document, your images might become distorted depending on how they fix it. Plus, you’ll be charged for their time – which is time taken away from completing the job. I wouldn’t want someone messing up my work. Just set up bleed in the beginning and export your file with bleed ready to go.
Don’t say I didn’t warn you. We need bleed. It’s good for effective print design. That’s why this is my first post here. Now, if you never intend to print out your document and just share it over email or the cloud, then you don’t need bleed. But, it doesn’t hurt to start with it and just export without it enabled.