In all my years of practice, a consistent frustration has been engaging with inventors that are reluctant to write down their thoughts and ideas. It is very important to understand that the scope of protection afforded by a patent can only be found within that patent itself. In other words, neither a patent examiner nor a court is interested in material that is not within the specification, as filed, when attempting to interpret the patent.
Of course, in some jurisdictions, such as the US, a court may very well consider actions taken during the prosecution of a patent application as narrowing the scope of protection. However, those actions are reflected in documents filed during prosecution.
Patent attorneys can spend hours mulling over documents provided to them by inventors in an attempt to draft a decent patent specification. You don't want to have them mulling over hastily written telephone messages and trying to recall things that you may have told them during a meeting. You should be able to write down everything that you need to tell your patent attorney. You can then hand that material to him or her so that there is no misunderstanding as to what should appear in the patent specification. Apart from ensuring that your thoughts and ideas are properly described, your patent attorney’s time can be more efficiently spent and this can save you money.
It is far more effective for you to spend an hour crafting an email to your patent attorney then it is for you to phone and to ramble on for half an hour while he or she tries to scribble down bits and pieces of what you're saying. Invariably, half of it is lost and another quarter is misunderstood. The same applies to meetings. Don't arrive with just the ideas in your head, expecting to convey all of them to your patent attorney over the boardroom table. Rather spend a day or two putting together some decent written material, including sketches and photographs, if necessary. Also, remember that we can't file your prototype. Drawings and photographs are far better than prototypes. Personally, the first thing I do when I receive a prototype is to take photographs. If these are taken on a white background and altered into black and white images, they can be quite effectively used for a provisional patent application.
Remember that simple notes and sketches will often suffice provided they represent all the information that you have. Sketches can be very important especially when annotated. There's a lot of truth in that old saying "a picture tells a thousand words".
When preparing your notes and your sketches, you should try to think of other uses that your product might have. Also, think of possible variations in materials, dimensions and other characteristics. For example, you don't want to be limited to a particular material that might be replaced in a few years’ time. Of course, unless it's absolutely necessary, your patent attorney should not limit you in this way. However, in many jurisdictions, you might find it difficult to enforce your patent against an alleged infringer that is making use of characteristics not specifically described in the specification.
The world of patents revolves about information and how it is presented. Your likelihood of success is inextricably tied to your ability to communicate your invention in writing.