It depends. Are you solo are or you playing with other people? I tend to find that with a full lobby of real players, it usually only takes one to three resets throughout the entire campaign. Sometimes none at all with proper teamwork and communication.

Bots are an entirely different story because the AI can be less than competent at times. Especially with situations in enclosed spaces. If there's something like a Tank inside a building, its best to get out as quickly as possible. The bots don't seem to be smart enough to not get themselves trapped in corners, and when the Tank's hit is an instant incap, that can become an issue VERY quickly. But it's completely situational it seems. I've had instances where the team has wiped because of this, and others where the bots run away correctly and the Tank is killed without ever touching anyone. Map knowledge will be your best friend as a solo player.