I remember this as well, generally for nasa launches, initially. But certainly isn't the case anymore for commercial crew. B1061 launched both Crew-1 & Crew-2,

I remember this as well, generally for nasa launches, initially. But certainly isn't the case anymore for commercial crew. B1061 launched both Crew-1 & Crew-2, B1067 both Crew-3 & Crew-4 (with a commercial launch in-between). Crew-5 was new and Crew-6 seems to be planned as well. https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_b...