169/365 Accents

This is less of a whine and more of a request for advice. I have a very difficult time understanding people with heavy accents — not people from English-speaking countries, but people from, say India or China. I work with several and while I concentrate on their words, I can usually only understand about a third of what they say. I hate to ask them to repeat what they said, but sometimes I have to — and often don’t understand that either.

What should I do and how many times is it appropriate to ask them to repeat themselves?