well, you could think of it as a very expensive repair. enlarge it and watch it crumble and you get back a repaired centre of the old size.
of course... if your region is crumbling, then the centre will probably crumble again soon.
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incidentally.. enlarging unit does not really decrease equipment damage. yes.. the % is decreased, but if anything, the enlarged unit cost even more time (maybe gold) to repair. 1 damaged sword out of ten is still 1 damaged sword when you add 20 new sword to it.
repair 1st, then recruit.