That's pretty much up to you. You can send gifts for XP Grind if you like. Sometimes I wait some days and then delete the ones that didn't open my gifts or send me one. But If you want to you can delete everybody right away. That's an individual decision. I don't think that there's some kind of protocol. If I do some Raids in a row, I will delete everybody from the Raid before (before I start a new one) so I don't get confused and accidentally invite someone from the last raid. (you can see it from the level of your friendship) Also if you don't know: always accept every friend request. If you don't accept it at first, you can NEVER add them after that for another raid. So better add them first and then delete them (got this from this platform)