Recruiting sufficient numbers of participant to reach your project goals often isn’t easy, but unless we’re careful our enthusiasm can cross the line from earnest persistence to over-zealous harassment. That is why it is useful to look at your project objectively and reflect on how potential participants will experience the recruitment strategy. If the strategy involves more than one contact with individual potential participants and it is possible they will consider the strategy annoying it is probably necessary to amend the strategy. At the very least there should be an easy mechanism for people to opt-out from any further reminders.