Sort:  

Couldn't agree more!

Someone who would have categorically demonstrated his real worth by adding/contributing to/for your gain/benefit/advantage/help or assistance is definitely of great significance and ofcourse possibly indispensable for you, (atleast for finite amount of time.)

For sure, I'm reluctant to give people who are supposed to be professionals in their field much time if they don't deliver a professional service.

Absolutely, that has to be the right approach, always and forever!.