The question of whether to play a game with or without expansions is one I think about more than I should. My general rule: learn the base game to satisfaction before introducing expansions. The base game teaches the core loop. Expansions add complexity that should layer onto understanding, not replace it.

Exceptions: games where the base game is genuinely incomplete. Scythe without any expansion is fine but the extra factions in Invaders from Afar address the faction imbalance in the base set. Spirit Island without Jagged Earth misses the best spirit designs. In these cases, adding expansions at the teaching stage is reasonable.

Expansions that I consider necessary from game one: none, actually. Even the expansions I find essential can be added later once players want more.