[Messi]

Right before I reach the endpoint of my Acid-Base titration I am told to rinse the walls of the flask with a little bit of distilled water from my wash bottle. Why is this?

I know it is to remove any titre on the walls of my E-flask, but why do I do it now, right before I reach my endpoint.

[Borek]

That's the best moment - if you do it much earlier, you can't be sure everything is in the bulk of the solution at the end point.