If someone invites you over for a playdate, you're "supposed" to reciprocate and invite them over soon after, right? How quickly after?

Lo was invited to her first in-home playdate last week--usually we've met people in a park or museum. And it's also a daycare family, so it's not like we were friends with the parents first, so the social dynamics are different. Social awkwardness, ahhhh! haha.