Published bleed and safe margin requirements from twenty printers, showing a 3.2× spread on bleed and 8× on safe margin for the same product.
The disagreement is the useful part
There is no standard here, and that is worth knowing before you build a template you intend to reuse. For a business card — one product, unambiguous — published bleed runs from 1.00 mm at FLYERALARM to 3.175 mm at a dozen others. That is a factor of 3.2.
The safe margin is worse. It runs from 1.59 mm to 12.7 mm, a factor of eight, for what is nominally the same instruction about keeping text away from the edge.
What follows is not "use the largest". It is that a house template is only valid for the printer it was built against, and moving a job between printers is a document-setup change and not just a file transfer.
Some printers contradict themselves
While assembling this I found several publishing different figures on different pages of their own sites. Vistaprint gives three different business-card bleeds across three pages. Next Day Flyers' FAQ and help centre disagree on both the standard and the booklet figure. Printivity gives both an eighth of an inch and a quarter for the safe zone on a single page.
There are also outright arithmetic errors live on printers' own sites. instantprint's A4 template page states that 210 × 297 mm becomes 216 × 306 with bleed; it becomes 303. KDP writes its bleed as "0.0125″ (3.2 mm)", where the inch figure is a typo of a factor of ten. Lulu writes "0.2 in / 2.08 mm", which is neither.
None of this means those printers do bad work. It means the spec page is not always the most carefully maintained page on a printer's site, and if a figure looks wrong it is worth a second source before you build to it.
Per edge versus total, again
Two of the twenty state bleed as a total across the dimension rather than per edge — 4over and GotPrint. Their published number is therefore twice what appears in the per-edge column here.
It is flagged in the table because it is the single most consequential ambiguity in this data. Everything else is a difference of a millimetre or two; this one is a factor of two.
Asked often
Which figure should I use?
Your printer's own, taken literally. There is no standard — the same product ranges over a factor of three between printers.
Can I just use the largest?
For bleed, largely yes; extra bleed is trimmed away. For the safe margin, no — a 12.7 mm margin wastes a lot of a business card.
Why does my printer disagree with this table?
Possibly because they changed it, and possibly because the figure here came from a page they have since corrected. Every row was checked on the date shown; tell me if one is stale.