Researching the challenges of IoT Development

I work at an IoT full-service product design firm, and I’m researching the most common setbacks experienced in IoT product development.

I would really appreciate some input, especially regarding these three questions:

How did you get started?

How long did it take from thinking of the idea to getting started (making the prototype, begin hiring a firm/build in-house team, etc.)?

What are some of the challenges you had during the process?

Thank you in advance.