How does project staffing actually work at consulting firms?

This is going to vary across companies.In some companies you have minimal say in the matter (staffing tells you), in others you have input (you get to select preferences or networking/building up a reputation gets people to vouch for you and select you) and in others it's all on you (you have to push hard to get yourself staffed).It's going to be dependent on firm/office so make sure to google a bit for each one and network with them to better understand.When staffing is in charge they're going to put you on projects that match your existing skillset/experience. They will also listen to Partners/Principals/Project Leads who request to staff you. Ultimately, whatever they say, they don't actually care that much about you and are going to optimize for timing + experience (which is why you need to “fight” for projects you want).In terms of managing that trade-off, this is a personal decision! You need to decide to what extent you want to expand/grow versus stay in what you're good at - everyone is different here!