You should make isthikhara each time you have taken a decision and place your trust in Allah.

Please watch this video about when to pray Istikhara:
https://www.assimalhakeem.net/when-to-pray-istikhara/

and this one:
https://www.youtube.com/watch?v=msaehIgYBJ0

A sister always assumed that one is encouraged to do Istikhara ONLY if one has some sort of confusion in decision making! Hence, if one is Confident of ones decision one does not make istikhara! is she correct? She suffered asudden unexpected loss,now she is confused should one do istikhara even if one is superconfident about ones decision(all this ofcourse in halaal matters)