Help me think of things everyone hires a planning professional for:

I'm an Architectural professional.

Some people hire Architects.

Travel Agent
Wedding Planner.

These are two things that people regularly have no objection to paying for. Admittedly the travel agency profession has changed. I understand that they're generally paid by the companies they book with and the customer isn't charged any longer.

Any information on rates, fees, or cost as % expenditure would help.

If you have your own data that you're willing to share, that would be great too.

Taxes
Life Planning-wills, trusts.
Ginger Extermination.

I am not sure about a Travel Agent, in a world with Kayak, Priceline, etc.

Business startup.