when to optimize database queries versus schema design? dont have a clear answer for this one.

hey folks, ive been mulling over database performance lately. sometimes i find myself spending a lot of time tweaking sql queries to eke out a bit more speed. other times, a quick schema redesign (adding an index, changing a data type) makes a huge difference. im curious about how you all decide when to focus on query optimization versus when its time to revisit the schema itself. whats your go-to indicators that point you towards one approach over the other