For example, Vampires allows Sims to become a Master Vampire. Most DLC comes with Aspirations that tie in with the theme of the pack.

They can get to the point that the Adulthood requirement appears. Also, those Aspiration Objectives that state 'Become an Adult' always give 0 and are meant to be barriers to Children/Teens from completing those Aspirations. Two things of note: Aspirations Milestones with the same name will be cleared on any Aspiration that shares those same objectives, meaning you will have a head start on completing those other Aspirations (usually in the same category) but not get the chance to get the Satisfaction twice. You may also prioritize certain Reward Traits first to help you complete another Aspiration later on. If, for example, you were expected to master a Skill you didn't want to, have many friends, or join a Career, it would help you to avoid selecting that. The following list's goal is to help you select Aspirations by providing knowledge of what you have to do in each.

Your first Aspiration choice matters in that your first Bonus Trait will not change after switching to a new Aspiration.

Completing an Aspiration earns your Sim a related Reward Trait, and allows them to select another Aspiration from any category. Unlike TS3's Lifetime Wishes, you may change your Aspiration at any time by pressing 'G' and going to the menu. The Sims 4's Aspirations are life goals that Sims may select, allowing them to complete a checklist of objectives to earn Satisfaction that may be spent toward Rewards. The Sims 4 Aspirations List Reward Traits, Satisfaction Totals, and Milestone Summaries

Sims 4 mod reward traits