The trouble spots on an install job are rarely the door itself. On houses from the early 1970s, the wood jamb framing the opening has often shifted enough that a new door won't sit square against it without shimming, and sometimes without rebuilding part of the frame first. We've also found openers wired straight into a junction box with no disconnect, which means an electrician needs to be involved before we can finish, not after. If your garage was converted at some point, or there's living space built over it, the header can be carrying more load than the original design called for, and we won't hang a new door on a header that isn't sized for it. None of this is common, but it happens often enough on a street of 1970s-built homes that we check for it before quoting a firm number. The honest limitation here: we don't do framing carpentry ourselves, so if the opening needs structural work, that's a separate call to a carpenter before we come back to finish the install.