Sterile Insect Technique (SIT) is an autocidal control method used against Pests and Vectors. While conceptually very simple, it can be difficult to set up in the field. That is why, it is sometimes successful, and sometimes not. We show that modeling, analysis and simulations can be helpful to limit the risk of failure in SIT feasability programs. We present some results obtained against Aedes albopictus and Bactrocera dorsalis in Réunion island, a French overseas department.