The single most common way a contractor brochure gets printed wrong is the assumption that a tri-fold is three equal thirds. It is not. On an 11 by 8.5 inch landscape sheet, equal thirds would be 3.6667 inches. Commercial printers publish something different: four of the six panel faces at 3.6875 inches and two at 3.625 inches. Those two narrow faces are the front and back of one physical panel — the one that folds in first. On a roll fold that panel gets wrapped by the other two, and if it is the same width as them its edge pushes against the folded spine and the whole piece buckles. One sixteenth of an inch of relief is what makes it fold flat. This builder encodes the printer's panel widths rather than dividing by three, and prints the fold guides at 3.625 and 7.3125 inches on the outside of the sheet.
The second trap is the order. You write a brochure the way it is read, but a press prints one side of a sheet at a time, and the two orders are not the same. The outside of the sheet carries, left to right, the tucked flap, the back cover and the front cover. The inside carries the three inner panels in order. That is why the flap is called the inside flap even though it is printed on the outside: it is still folded in when you open the cover, so it is the first panel a reader meets on the inside. Its reverse face is the inside-right panel, which is why inside-right is the narrow one on the inside sheet. Get this mapping wrong in a page-layout program and you get a brochure whose back cover is where the flap should be — which is usually discovered after the print run. Here you never touch it: you author the six panels in reading order and the exporter does the mapping.
The third trap is copy that does not fit. A panel is about three and a quarter inches of usable width once you hold the printer's 0.25 inch safe margin off each edge, and roughly eight inches of usable height. At ten point body copy on fourteen point leading that is about 45 characters per line and 34 lines under a heading — a little over 1,500 characters per panel. Most people write two or three times that into the inside centre panel, and it looks fine on screen because a screen has no bottom edge. The builder wraps your actual copy at the actual column width, counts the lines, and flags the panel as overset with the number of characters to cut. That is the check "it looked fine on screen" exists to replace.
The fourth trap is legal, and no competitor brochure template mentions it. Several states require a contractor's licence number to appear on all advertising, and a brochure is advertising. California requires the number in all forms of advertising under Business and Professions Code section 7030.5, with the board's own rule requiring it be legible and unabbreviated. Florida requires the certification or registration number in each offer of services, proposal, bid, contract or advertisement, regardless of medium. Texas requires an electrical contracting company's advertising to carry both the company name and the licence number. Those three are the ones read and cited in this builder. For any other state it prints "not evaluated — check your state board" rather than inventing a verdict, because there is no authoritative fifty-state table to copy from. It also checks placement, since a number sitting in a form field and not assigned to a panel does not print at all.
The last set of checks are the claims. An unqualified "Licensed, Bonded & Insured" line is the most-printed sentence in this trade and the least substantiated one: the builder flags it when the licence number, the insurance carrier or the bond amount is missing, since those are the three things that make it checkable. A guarantee headline with no terms gets flagged too — the FTC's warranty advertising guides say an advertisement mentioning a warranty should disclose that a buyer can see the written warranty for complete details before purchase, and "satisfaction guaranteed" represents a full refund on request. Testimonials get the FTC endorsement guides applied: the quote must reflect the endorser's honest experience, a material connection such as payment, a discount or free work must be disclosed clearly in the same advertisement, and before/after results imagery is read as typical unless you say otherwise. Your front cover should still be a line about work that passes inspection the first time — none of this is a reason to write a legal notice on it.
An electrical brochure is read by people deciding whether to trust you with a panel. Credentials do more work here than adjectives — a master electrician on staff, permits pulled, inspections handled — and in Texas the advertising rule wants your company name printed right alongside the licence number.