Depends on which case. Civil juries and criminal juries have different amounts of people and when choosing a jury each side gets a limited number of challenges and there are different challenges. Some challenges are for cause, some just because. So picking a jury - especially for a criminal case - is a talent which firms MAY use certain specialty lawyers for.
So it depends how a lawyer wants to “spend” their challenges. They read the jury pool they’re given and play a game of Stratego.