How many Kerbals do you usually have?

[W. Kerman]

In career, as soon as I get the SAS probe, I start having one Kerbal. (Scientist!) Before that, I have to suffer through having kerbals fly my craft...  

[Magzimum]

Aww! Sending lone Kerbals on interplanetery missions is criminal!

I typically send between 3 or 5.  But lately I have been doing a-typical missions, with 25 Kerbals to Jool, and soon multiple mission (a fleet, basically) to Dres, because Dres needs love, with my entire crew of 27 Kerbals, distributed over multiple ships. 

[Hands MCML]

I typically do not use more than 3; Pilot, Engineer, and a Scientist. The only times I have more on a flight is for tourists. I also limit my potential crew to 12, (level 2). Some contracts require more Engineers or Scientist on board.

[elpollodiablo]

Minimum crew is 2, but just at the very beginning (except the very first launch).

First Mun (or equivalent) landing is with 3 (altough apollo style mission).

Then it's at least 5 (pilot and backup pilot, 2 scientist, 1 engineer) but basically as much as possible (i usually play with life support mods).

The only reason is a mod called "final frontier". I like to spread the "first" plaques around my heroes (orange suits plus any badass's that comes along).

[Kerbinchaser]

1-3. Usually in the MK 1-2 pod. 

[slubman]

Once I unblock the MK 1-2 pod, all my missions are based on teams.

These teams all have 3 members, and the membership of a team does not change.

If a team member is KIA, the rest of the team become inactive and is sent on the Island.

So depending of the mission I will send a multiple of 3 kerbals on it.