The best option is to use IDLE reverse when operationally safe and feasible. This is the best balance of cost vs. options for safety. This allows the selection of more reverse if required for unforeseen circumstances without having to wait for them to deply
That is a fallacy and a potentially dangerous one at that. If you use idle reverse after touch-down and then as the aircraft slows down you realise that due to high groundspeed towards the end of the landing run you need reverse in a hurry - then it is too late because by then the reverse thrust efficiency even with full reverse applied is degraded. From 100 knots down, reverse thrust is less effective and markedly so below around 80 knots.
Idle reverse is probably better in the high speed regime than no reverse but not by much. You can count on hot brakes when using just idle reverse. The Boeing 737 FCTM states that the use of minimum reverse thrust as compared to maximum reverse thrust can double the brake energy requirements and result in brake temperatures much higher than normal.