Super SG-1 nerd here, they often speak of the “marines” that get sent in to scout places first.
That said, the “front-line team”, as they are called here and there, gets priority on a lot of the big missions.
Besides, you really think sg-12 is capable of tackling a galaxy-ending scenario every 6-12 months? They can barely sort their crayons at chow time.
Q was right about this time line, not the Prime Timeline.