This is the 8334th most frequent Catalan word.
desgastar
"Desgastar" means "to wear out" or "to erode."
Here, 'desgastar' is used reflexively ('es van desgastar') to indicate wearing out or deteriorating due to usage or time.
Les sabates es van desgastar amb el temps.
The shoes wore out over time.
In this sentence, 'desgastar' metaphorically means to use up or expend energy.
No cal desgastar les energies en discussions inútils.
It is not necessary to waste energy on useless discussions.
The verb 'desgastar' here directly describes the physical act of wearing down or eroding a material surface due to friction or pressure.