Creating a model or prototype will allow you to get the best approach to manufacture the unit you've invented. It can be helpful for all sorts of things like determining where to put labels, what are the shipping weight will be, the best way to package it, what it may cost to manufacture it, also to get feedback from test users. It's a valuable tool to work with.
If you are planning to attempt to raise money to manufacture the brand new product yourself, or if perhaps you're demonstrating it to a possible client to acquire a big order, you will need the prototype if you don't currently have a production unit to demonstrate or demonstrate.
People just don't have much imagination. You are an inventor, and that means you have an imagination. Before you can invent something you have to have the idea...also it takes imagination to create fun new ideas. Other people, you will find, simply do not have the imagination or vision that you simply do. Help them.
With an above average prototype or model, your audience needn't provide an imagination. It makes new product "real" for them, adding tremendously to your credibility. Having a good prototype will help sell the item even if it isn't even just in production yet.
DON'T delay prototype building until after you file your patent application. You will probably discover flaws or new features, or discover possible manufacturing problems. With rare exception prototyping is very worthwhile. There are typically unexpected discoveries from construction of InventHelp prototype service.
Tests are very important. A prototype enables you to actually test your invention inside a meaningful way. You can attempt it with individuals other than yourself if appropriate, and you should discover that others could have constructive criticisms and suggestions that may be very valuable.
By searching online you'll find model and prototype building companies who is able to build it for you personally unless you have the skills yourself.
Sure there are instances when a prototype just isn't practical, when it is too expensive for instance, but when it really is at all possible, I highly recommend an invention prototype or model be manufactured.