If you are thinking “I can’t have any negotiating leverage – there are plenty of other people capable of solving that problem“, remember that replacing you means:
1) Separating your trustworthy competitors from amateurs and scammers
2) Waiting for the “real deal” experts to become available
3) Shouldering the cost of expert switching
What’s that last cost? That’s the test: think of your colleagues in the field, working on their projects. If someone scrambled, mixed up who is assigned to what project, and from tomorrow everyone in your field shows up at someone else’s project and has to continue working until the project’s end – how much damage was just done?

Probably – plenty. In some fields, there is a wide variety of outcomes even from professional-level services. In other words, the question is not simply “Has [service] been delivered or not” but also “To what degree has it been successful”.
If the second question is nonsensical (e.g. the toilet is either unclogged, or still clogged) then the service is truly commoditized, and the only leverage you can have is personal or emotional connection.
However, if omitting the second question would render the test nonsensical (e.g. have you been coached or not coached) then the field is not commoditized, and you CAN benefit from the field’s “natural” leverage.
If that’s news to you – what will you do differently from now on?