Opportunity cost
Currently I'm pitching on a huge project; a train-the-trainer roadshow made more complicated by being pan-European and with the usual disconnect between the centralised marketing function in Paris and the regional sales teams.
I can already guess that the project will swallow every available moment of my life between now and deadline with multi-country teleconferences, endless rewriting of PowerPoint slide decks and one-line emails about the need to install an updated version of Adobe Acrobat. Because I won't let myself to do bad work I will do all of this regardless of the financial deal I strike this week.
Whilst I want the job and I'm prepared to handle the hassle that will come with it I'm also aware of the opportunity cost of getting the pricing wrong. It's going to be hard enough dealing with all the frustrations brought about by the client's internal politics without having to turn down more lucrative work because I'm overcommitted. If that happens I'll really struggle for motivation. This is what undercharging feels like and it's when I do my worst work so I need to factor a sense of opportunity cost into my pricing.
The jobs that have hurt my reputation the most have always been the cheapest.