Google earth is really a good invention..
but
can be worth looking at the imagery aqquisition date to get an idea of what time of day or even, as John says, what year.
quite recently I was thinking of a road trip around Iceland and was hunting snowcover images from the previous week (not in google) while trying to get the right vehicle .. I abandoned Iceland and went to Croatia instead.. Iceland was postponed for 6 months... my only employment was satellite imagery and GIS..sadly not any more..
John