Spending money is difficult. 

Some can taste the difference with a better steak.  Some electronics that are cheaper fail faster.  Sometimes though you just don't know if the increase in cost provides even a linear increase in value.  Sometimes the increase is exponential.

When it comes to spending money on a Consultant, the experience they bring can save you money for years to come. 

If you are planning on developing a new product or moving forward with an updated technology, you obviously want to first invest in your own assets: your full time employees.  They retain the business knowledge that you need.  They are your muscle. Don't believe a one week crash course on the latest technology will give them the skills for making decisions now that will affect you for the life of the application.

An expert is someone who knows all points of failure in a given realm.  What you don't do is as important as what you do.  Remember to evaluate and reevaluate your road map frequently.  If that plan isn't improving, it is declining.  Provide your team with the insight from a consultant to address that plan and how it's being used. 

Sometimes the solutions seem easy; "Go directly towards the goal."  Unfortunately, the destination is a moving target.

Ask questions.  How hard will it be for us to scale this current solution?  How will this solution work in new, evolving environments?  How can we update individual key components? How will we know that a fix didn't break something else?

Switching between operational, tactical and strategic planning is very difficult.  Invest in the talent that can direct you over the mountain and can build you the bridge across the canyon.

Spend wisely to hire wisdom.