It's probably a good thing I don't get everything...


I was actually hinting at the idea that the battle strength doesn't need to equal the administrative formation strength.
An obvious example for this are administrative and basic training units which often stay at the garrison when the formation deploys. This might be modified for combat troops (which are the most likely candidates for heavy losses).

A deployed brigade could have several battlegroups and a support group.

Army developers might assume that this brigade would sustain heavy losses in its mission (I'm most likely not writing about an expedition cabinet war here).*
An almost obvious choice would be to add one battlegroup "too much" and keep it under corps control in a calm area until it gets exchanged with the most exhausted battle group. This would start a permanent rotation which could enable the formation to keep going at useful strength for quite long.

Another army developer might assume different, shorter missions.
He could instead add an infantry battalion as dedicated security element to the support group. The battle groups could be reinforced from this initially not very battered battalion when their own infantry is too much exhausted or if the mission (terrain) requires more than the usual battlegroup's infantry strength. This extra infantry battalion would serve as a brigade reserve, and it would take a self-disciplined Bde Cmdr to use it like this.

------------------------------------------------------------------------

Finally my reasoning about cavalry / scouts / armoured recce and the likes at Bn to Div level: This is an obsolete concept.

Scouts cannot move faster than combat troops today - unlike at the time of horse cav when cav was able to march several times as far per day as infantry or even artillery.
The armoured truck scouts of WW2 had a range, speed and maintenance needs advantage over WW2 tanks as well.

Today there's no such time difference and a well-trained formation could (if it avoids many typical but avoidable shortcomings) move many times as fast as in WW2. Today's armoured forces would not need to wait for foot march infantry forces.

This loss of a speed advantage puts the classic armoured recce approach in question.

The (AFAIK) best and most encompassing answer would be to pre-position scouts and surveillance teams up to a huge depth (~300 km). No matter which direction your Bde turns to, it would always have scouts ahead and cav for security available for its flanks.
This is obviously not practical with organic manoeuvre formation scouts.
Scouts and surveillance teams (this excludes dedicated FOs for fires) should be directly corps-attached troops.

This does btw also solve the issue how to cope with uneven cav/scout losses among Bdes. Scouts would always be available (except if the campaign sucks globally).
The security and close recce job should therefore be assigned to combat troops, as it happens in many armies of the world.

The U.S. Army sported a huge amount of talk and blather about "situational awareness". Shouldn't it be obvious that having scouts already at or close to locations which only very recently got your attention rather than to send them out when you become interested in a location?

The quite disappointing state of Operational Art today is the culprit. A look at a brigade alone cannot reveal the needs of a Corps or Threatre commander and whether the Bde is prepared to meet these needs. Sadly, a lack of corps-scale real and free-play manoeuvres means that we don't learn enough about our shortcomings on Corps level.


------------------------------------------------------------------------

About my "*":
It's perfectly fine to use all available forces (even if only as reserve) when you look at a battle (= most common and most influential training scenario for brigades).
It's different for a series of battles (campaign). The Eastern Front 1941-1945 saw man fresh or refreshed armour divisions joining the front with hundreds of tanks. They lost extreme quantities of tanks and had to make do with just a few dozen tanks for the final weeks (if not months) before they were withdrawn for rebuilding.
Paradoxically, German generals recognized that losses are smaller if available forces are smaller (the opposite was true in fighter vs. fighter air combat, such combat dynamics are really interesting!).
It would have been better to sustain a mediocre strength.

A campaign leader (Corps Cmdr) thinks even farther; he is concerned about the culminating point of attack; how far he can advance and how much he can achieve until he needs to let his forces rest and regain strength.
The culminating point of attack is a most important variable - one of the great levers for short and not terribly brutal wars.
The sustainment of combat power among the formations is of greatest interest for this.
The far culminating point of attack of German forces in 1940 explains why Germans conquered France in six weeks while the Western Allies took six months for reconquering it (despite much, much better motorization).
The quick advance in 1941/42 and slow withdrawal in 1943-1945 on the Eastern Front can be similarly attributed to the inferior Soviet preparations for long campaigns (most notoriously their lack of vehicle repair capabilities in the field).