If there are more sanctions to announce, why weren't they announced before?

Every now and then, I read about a new sanction that is being brought to bear on one of the world's pariah states. The latest such is Canada, France and the UK are sanctioning Israel in a small way by banning the import of goods from the illegal settlements in the occupied West Bank. 

My first thought was "What? We buy things from the occupied West Bank? They can actually grow things there?" My second thought, though, was "Why the hell did we not impose these sanctions before?"

It's the same with Russia. Canada and most of the civilized Western world has imposed various sanctions on Russia since its invasion, and its ongoing bombing, of Ukraine. As recently as June of this year - four-and-a-half years into the war - Canada imposed new sanctions on 162 "people, entities and vessels". 

Which raises the questions of "why now?" If these are legitimate sanction targets in relation to Russia's illegal war, why were they not sanctioned four years ago? Why were the earlier sanctions not designed to include all possible targets, for maximum effect? Why wait until now to announce a few more piecemeal sanctions? Was it just for the sake of having something to announce, to be seen to be doing something?

It does seem to be more about playing politics than a serious attempt to bring about a halt to the war. And I'm not saying that only Canada is guilty of this - all countries seem to be doing it.