I'd say a cute selfie maybe as a profile picture twice a month. Photo's with multiple people are fine, as long as you don't just get a selfie with everyone you meet during your day.
I think they only way to get away with it is when Instagram post to Facebook. Rather than you posting a photo to Facebook. If that makes sense.
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Girls that post a new selfie everyday are the WORST and the ones the post every outfit they wear because the world has to know. It's okay for a formal occasion, but no one need to know what $29 dress you're wearing to the clubs or to go shopping.