When teaching long term trach care, clean technique is sometimes the best expectation. Sterile would be ideal but not practical.
This is going to be facility specific and will depend on the suction catheters available.
For home care and some LTC facilities, multiple use catheters are commonly used. These may be in the form of a sleeved catheter that is used for 24 hours. It is also known for some to reuse what would otherwise be a single use catheter in home care settings because of a limited amount of catheters supplied.
Hospitals (and LTC facilities) will regularly use inline suction catheters which are not necessarily considered sterile since they have been used and may also have seen the circuit opened or disconnected from patient/ventilator or laid on the bedding when moving a patient with it t-pieced onto a trach open to air at one end. No special order is required from a doctor for the type of suction catheter if it is accepted within the P&P of the facility.
Example of an inline multiple use suction catheter.
Sleeved suction catheter commonly used in home care and LTC.
Check your facility for a written policy for both nurses and RTs.