Or if you had a character with a wand of magic missiles and 100 charges back in the day, then you had your at will combat cantrip then.… and then there's cantrips, which seem to freak people out, but if you've played with Warlocks and at-wills for a decade, you've gotten used to the idea of at-will magic that just isn't that impactful, not, well, making much of an impact.
In my experience at will combat cantrips aren't worth worrying about. They conceptually do much the same as starting with a low powered wand, and are basically just flavor dressing on throwing a dart every round.
On the other hand, at will noncombat cantrips have a huge impact. Having things like detect magic, create water, light, dancing lights, and forth be at will does big time change the flavor of the game especially at low level. Back in 1988 I experimented with making the old 1e cantrips that could do almost nothing 'at will', and within just a few sessions rolled back that rule to 'caster level times per day' because it was in play detrimental to the players approach to the game (gifted with the ability to do something, they assume they should do that thing). But having played for example Pathfinder, non-combat cantrips will never be an 'at will' thing in any game I play, because a caster essentially has infinite resources. The ability to destroy something is nothing compared to the ability to infinitely and abundantly create something.