Sooner rather than later for prototype samples is the way forward.
Product development is a horse race, get there first and win. Making a rapid prototype sooner rather than later, even if it is not the final design, is the way forward. There are some obvious benefits and knowledge that can be quickly obtained from making a physical rapid prototype. Such as confirming that your design actually works as intended and being able to test your product early to see what changes might be needed.
But more important for me…spending money early on rapid prototypes is all about saving you money over the life of your project and delivering you potential cash injections earlier, which you will need.
Time is your enemy. Right now, somewhere in the world, someone is thinking the same way you are and is developing a product similar to your product. Is that statement always true? No, but you should be thinking this way and be using your known or unknown competition as a motivation to get to market faster. The faster you get to market the more product development money you save. Prototype samples speed things up so make prototype samples early on.
Salaries cost more. The cost of rapid prototypes is a valid concern and should be looked at carefully. But in my experience, this cost is often over analyzed. I had a client about 10 years ago, we went back and forth on the cost of prototype samples for 3 months before they decided to pull the trigger. A team of 5, all drawing salaries from investors money for 3 months. Salaries (generally) cost more than prototypes, prototypes help you get closer to a positive revenue stream, so choose prototypes. Each situation is different, but if the cost is reasonable then go for it, you have to spend the money eventually anyway.
Physical samples gain investor confidence. Physical samples make it real. Unless you have the breakthrough product or technology of the century you are unlikely to impress investors without real samples. Industrial sized products are a different story, but for consumer-sized products, I would never invest in something if the presentation is only a computer model. Showing me a physical sample tells me that you believe in your project and invested your own money or that other investors have already qualified you and given you money. Physical samples turn you from an idea guy into someone I can take seriously and invest money in. I am investing in you as much as I am your product, show me you believe with some great prototype samples.
Physical samples gain retail/distributor confidence. This is where you want a rapid prototype 2.0. Meaning a perfect prototype, meaning that the person you are meeting with thinks that you are showing them a production piece. There are 2 ways to get an outside cash injection into your project i) investors, and ii) purchase orders. Purchase orders give you freedom from investors, but the only way to get purchase orders are by killing it in your sales meeting. Perfect prototypes give you a much better chance to impress in meetings and win purchase orders.
My experience tells me this. If you are judiciously aggressive in making early prototype samples, you simply save more money in the end by bringing your product to market faster and you have the chance of winning cash injections into your project. Sooner rather than later for rapid prototype samples is a great way to win with product development.