To paraphrase a previous employer's strategy: fixed fee projects are for ones you plan to do over and over where it makes sense to invest at getting good at them.
The first one you lose a bunch of money, the second you might break even if you are lucky, and the tenth onward you make a bunch of money.
The first one you lose a bunch of money, the second you might break even if you are lucky, and the tenth onward you make a bunch of money.