I have done cell cultures in the past (during undergraduate and master's) where I used 10x PBS (for rinsing cells) directly from the manufacturer's bottle without any issues.
Now that I am doing a PhD, I am inclined to question why protocols suggest that "sterile" 1x PBS should be used for cell culturing? Why sterile and why 1x?
I understand sterility is to prevent contamination, so why does it not matter if other reagents such as media, trypsin, etc are not sterile?