At the very least once a month. But if they are communicating with you via the stream, team mail or their leadership page, I suggest you send comments to them often.
Think of it this way, if they are communicating to you and you never comment, thank, or acknowledge them it is like a shot in the dark for them to know what you need from them.
You will be a Sponsor and Co-Sponsor hopefully one day. Remember we are all on the learning curve and communication is needed both ways.
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