I take a glance at the windows .... all of them.... starting with the front upstairs... if there is bird poo i soak it.... then leave it. and go back nearly last.( if upstairs)
if i see anything else whilst i am cleaning, like green blobs, or brown bits, .... i still soak them and do them last...
it falls off after a soak...
Upstairs , you can tell by the flow of water/droplets if there is anything stuck on.... rinse and go back.