If you were at a job for a while and the people you got along with started slowly leaving would you still continue to be there or quit as well?

Depends on the type of job you're doing i guess.

If your job is something team based and it works for you i suppose you might think it's time for a change if you can see trouble ahead.

When lots of people leave sometimes owners or managers decide they want to implement new working policies or change the things that make working there good.

As long as the replacements were cool, I’d stay.

I would continue to work there, but I'd change my brand of mouthwash just as a precaution.