I been wearing clip in units for 5 years. i rotate my clips often.
I do get these thin bald spots but after a rest in that area it fills in but is of course baby fine . Although still enough for me to wear clip in units.
So rotation or moving your clips around and not sleeping in my unit is is biggie for me . I have also wore head band to secure my piece as I leave some clips un clipped to rest the thinning/bald area.