The indicates that you have made your last transmission. If you have completely finished the QSO and wish to remain open for business you just naturally don't put anything at all after your call. It saves them needless calls. The correct procedure is just as easy to learn and use as is the Sloppy Joe type. If you are just starting on your ham career you might just as well start right.
Bad habits are difficult to break.
If you find it hard to remember what to send and when to send it make up a sheet with standard forms and keep it on your operating desk. Once learned it isn't forgotten. This particular scream of mingled rage and pain has been heard since Marconi first sent three dots across the Atlantic. Do not send a single R if you missed any part of his transmission. Just sent a break sign, BT, after your call when you go back to him, if you missed anything, and tell him what you missed.