Producing a model or prototype will help you get the best way to manufacture the device you've got invented. It can be useful for all kinds of things like figuring out where to put labels, what are the shipping weight is going to be, the proper way to package it, exactly what it cost to fabricate it, and also to get feedback from test users. It's a valuable tool for you to use.
If you are planning to try and raise money to manufacture the newest product yourself, or if you're demonstrating it to a potential consumer to get a big order, you will need the prototype if you don't currently have a production unit to demonstrate or demonstrate.
People just do not have much imagination. You're an inventor, which means you will have an imagination. Before you can invent something you want the idea...also it takes imagination to generate great new ideas. Other folks, you'll find, simply do not have the imagination or vision that you just do. Help them.
With a decent prototype or model, your audience does not need to have an imagination. Celebrate new product "real" for them, adding tremendously to your credibility. Having a good prototype will help sell the product even if it is not even in production yet.
DON'T postpone prototype building until when you file your patent application. You'll likely discover flaws or extra features, or discover possible manufacturing problems. With rare exception prototyping is quite worthwhile. You can find typically unexpected discoveries from construction of inventhelp innovation.
Tests are very important. A prototype allows you to actually try out your invention inside a meaningful way. You can look at it with people besides yourself if appropriate, and you will then realize that other people could have constructive criticisms and suggestions that might be very valuable.
By searching on the internet you'll find model and prototype building companies who can assemble it for you personally if you do not hold the skills yourself.
Sure there are occasions when a prototype isn't practical, if it is too costly for example, however, if it's you can, I recommend an invention prototype or model be produced.