I've worked as Quality Manager at several companies and also as Quality Assurance Engineer (where the boot is on the other foot).
The companies I've worked at (over 25 years) vary from oil regulators, high pressure cleaners, F-16 heat exchangers, centrifugal pumps, and a couple more. I've had more than a couple of them certified.
The problem isn't so much ISO 9001 as the person or persons writing the handbook, procedures and instructions that seem to get carried away with what I describe as "writing diarrhoea" where too much is written in too great detail. Also known as BS.
The biggest mistake most make is writing to impress the outside world as to how good they are rather than writing what is necessary and essential to the company itself.
If I had to invent rules then they'd be along the lines of:
1) Never write more than is necessary to achieve official company policy and goals. A Quality Manual is written for the company and
not for the customer, for which it's only information.
2) Operations or procedures that can cost injury or money if not followed are the most important to describe.
3) Apply common sense and allow for the fact there is often more than one way to do things.
4) Get all in the company involved somehow. It's a joint effort.
It's always much easier to add something on (tighten up) than it is to try and remove something, especially with a "theoretical" auditor looking over your shoulder.
Shop around and find a company that can give authorization and that you feel you can work with. Is it expensive? Depends not only how big your company is but also on how much you've written. The more you write the more that has to be checked.
Don't be one of those companies that, the day after certification, start to figure out how to circumvent what they've written.
If anyone wants me to go into more detail on this subject just let me know - I'm free
An after thought. If you are a sub contractor, then it may reduce your insurance and liability costs if you are ISO 9001 certified. From some major contractors it is a must to minimize their risk and liability. Windturbines for example.