What do you usually do once your sim completes their aspiration?

I usually pick a new aspiration as well. Sometimes I even play a couple aspirations at the same time with my Sims when I can't choose just one or I know one of the steps is going to take me long to complete.

Although I'm happy enough if they complete only one in their lifetime, I don't worry if they are getting old and I'm not done with their second aspiration yet.