in my field if you accept all of these requests from recruiters, they will badger you to go to lunch or stop by your office to introduce themselves until you agree to, which is a big pita for me, I don't got time for that stuff telling you about my job and background for an hour. when you're ready to look for a different job, these people will still be there and they won't care that you gave them the cold shoulder because they'll still want your commission.