This is a great question. Advertising is one of those things like building, painting, gardening, cooking – you can do it yourself or you can get an expert to do it for you.
The question to really ask yourself is what is your skillset? If you are a great promoter then you can do more yourself. But if you are great at the technical side and customer side of your business, maybe you need to get someone else to do the promotion so you can focus on what you are good at.
The other thing an external partner does is they work with you to really understand what it is that makes your business different and better, then and only then will they start to create the advertising to promote your business. This external perspective can be invaluable.
On top of that they will have a point of view on what works – what the right mix of brand and promotion you should do – what channels will be right for your audience. And they have the experience of working across a number of clients and seeing what is working and what isn’t.
Yes it will be expensive – but it will have a much better chance of working than doing it yourself…