Or if you really want to play the fixed price game, better add a _large_ buffer which you may keep should the project miraculously complete on time. You transfer the risk from the client by doing fixed price work and risk is expensive.
And of course, _every_ client change, goes through a process that evaluates it for additional cost that gets added to the bill. I think this change process is a considerable money earner for consultancies.
But yeah, personally I always just charge a day rate.
However there's a case for fixed pricing and it can work to your advantage: Think of a difficult task or problem that you already solved in similar cases - maybe you already have the heavy foundation of that work ready as a template, maybe you automated complex, repeating steps. Or just think of a simple task that has huge value for your customer. Pricing shouldn't always depend on how long it takes you to finish a project.
