How many wards do you need before you saying "no Mia"

Seriously, how many wards do you need before you stop blaming whatever lane didn't ping because they didn't see that their laner left because they were in store, or perhaps they were looking at why they died. We have two free wards now, but still, "Mid no Mia" "Thanks for the mia, not" How many wards do you guys need!?