Do not use, “Thanks in advance!” It makes you sound rude.
Many careless people use this phrase.
- If the person grants their request, then they are too lazy and disrespectful to say a proper, “Thank you!” What? You are too busy to pause and thank someone?
- They presume the person is going to grant their request, but maybe the person has a good reason for not giving them what they want.
If and when your request is granted, take time to give them a careful and sincere, “Thank you!”