Can I use a different charger for my Samsung Galaxy S3?

[AC Question]

My sister also has a Galaxy but she told me that I should stick with the charger that came with my phone. But my charger is in bad shape and I want to get a new one. Will my phone be fine if I just buy a new charger and use that one or should I buy a charger specifically for my phone? I have used other chargers before and my phone is still working fine, sometimes. I would just like to know what my safest option is.