I used to work for an Observatory, (Lick). I once asked some guy there, who just happened to be one of the world's renowned lens designers, how long it takes him to design a lens system for a telescope. He looked at me and said, "Well John, it takes about 3 months", and then after a pause, "And about 30 years".
So though cutting out a snow screen takes no time at all, there is wisdom untold in knowing where and why to apply the scalpel.
John
matt's snow screen clean for me required about 15 seconds and a pen knife.