If the number of dead and wounded in a unit reach a high enough number, the remainder is useless as a fighting force.
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That’s may be the case.
However in this case, the unit can be pulled out and reconstituted. This seems to be happening there all the times. Both on the Russian and the Ukrainian side.
What it means, that it is only temporarily ineffectiveness.
Obviously dead are dead, wounded - depends on the wound - are either done or on temporary disability.
In the utmost cases (WWII comes to my mind), even soldiers with missing limbs could still be used in some fashion.
The article that I am imperfectly recalling made the point that the peculiarities of the Russian military made reconstituting a force quickly after withdrawal particularly difficult.
The parachute regiment that was the focus of that article was expected to be out of commission for years.