Clients send me a lot of long resumes. Surprisingly, many say things such as "I know you're usually not supposed to have a long resume, but this is what people in my field want to see." No, they don't. (Project Managers - I'm talking to you, too!)
A resume used for job search purposes should always be as concise as possible. Now, "concise" will look a lot different for, say, an Entry Level candidate compared to an Executive Level candidate. Notice the emphasis on for job search purposes.
Project Management - as an example - often requires what is informally referred to as an "on file" resume. When companies (or consulting firms) are deciding which Project Manager(s) to assign to specific projects, they really do need to see the complete, and detailed, picture of a Project Manager's background. On file resumes typically provide thorough details of project experience and help decision makers to fully understand who will align best with which project. This makes perfect sense.
Many people - and we'll keep picking on Project Managers here for illustrative purposes - having witnessed this important use of on file resumes, believe that this is the type of resume that should be used when conducting a broad job search.
This is a mistake. Yes, hiring managers / consulting clients, etc. do want to see these types of on file resumes for project assignment purposes. However, very few recruiters / hiring mangers will want to see this type of resume as part of the initial applicant screening process. During the on-boarding process, HR will likely ask the selected candidate to create an on file resume for the aforementioned purpose.
A long resume is never a good idea when searching for a new job. It's meant to be a hook. If you, like many Project Managers, fall in the "this is what people in my field want to see" camp, you may want to have two resumes on hand but never lead with the detailed version.