Final answer:
The question asks about the required frequency of sustainment training for specific military operations. The exact timeframe is not given in the question, but such frequencies are usually determined by the military's SOPs or regulations to maintain readiness.
Step-by-step explanation:
The question pertains to the frequency of sustainment training for various specialized military operations. Such operations include Rappel, Fast Rope Insertion/Extraction System (FRIES), Special Patrol Insertion/Extraction (SPIE), STAbilized Body Over A Line (STABO), Ladder, and Helocast Operations.
These operations are high-risk and require regular training to maintain proficiency, but the question does not specify the exact timeframe within which this training should be conducted prior to training events.
Normally, the required sustainment training frequencies are specified by the military unit's Standard Operating Procedures (SOPs) or other regulations, which are adhered to in order to ensure that operators maintain the necessary skill levels for operational readiness.