How often do you train with other Service Branches?

In 27 years I trained with the Navy twice. In Iraq I also had a Joint MTOE with Air Force, Marines, Navy and Army but that was Ops not training. Both times I trained with the Navy it was training for insertions, by sea, behind enemy lines to set up commo links for upcoming Battalion Level Infantry Combat Ops. The first time as a SGT/E5 was an eye opening, seemingly career ending, catastrophicly difficult problem. I and everyone else, found out to late that the radios used by the Navy and Army are only about 90% compatible. Therefore the SOIs produced for us to use with the Navy were more than 60% unusable. The first day everything was fine but when time came to change Freqs our radios could not load the Navy numbers. Once I found that problem I went through the whole book and found bunches of unusable data that had to be worked around. My company and battalion commanders were ready to fire me because they thought I was incompatant. I had to explain the problem to my Bn SIGO over the radio, from the field, he was also unaware of it. Then he had to publish a hand written work around to fix the problems in the middle of a Bn Combat Training Exercise. The second time as a SFC, I was aware of the problem ahead of time, when no one else in the Bn was. So I was a hero, we a had a hand published work around SOI published and handed out before the exercise started. We briefed leaders and radio operators on the difficulty ahead of time. I actually got an award for the positive effect it had for preventing the same kind of problems we had when I was a SGT. So yes we can suffer or benefit from training with our sister services. I am sure there are probably other similar difficulties in inter service OPS.

All the time. Of course I am a joint plans officer. Yeah there is a lot of benefit from it. Each service can learn what makes the others tick. Gives you better SA on why certain things are happening in the real arena. As a air guy doing CAS with the ground guys. I always general idea what was going on. But once I got to talk to some of them, certain things that occurred make more sense now the I reflect on it.

Can't speak for today but 70's-early 90's we had a joint Army Marine exercise with Ft Bragg and Camp Lejune involved, And I can't remember all the exercises in Europe with the US Air Force and elements of the military from Germany, England, and others....