I have never had one for either of my girls, I have been offered ones, but for me, I literally sleep with my ears open wide!
I can hear Maddy snoring all the way in her room, with her door almost closed, even with Tv on in lounge!
As for Indah I can hear her when she starts to wake, but as she sleeps thru too til 8amish, I hear her stirring & talking so i get up & go to loo, if not up already, I simply hear it all & it keeps me awake, I think a monitor would just not get any use from us!