Aerial photography, while much easier to obtain given the current digital camera & GPS technology, is still very expensive and time consuming to fly, post-process, geo-rectify and serve on the internet with an Internet Map Service. So, most areas only update their imagery every 5 years. Some "poorer" states a/o areas are at even longer intervals at lower resolution (3 meter pixels) while some "richer" areas fly every 2 years at higher resolution 6"-1' pixels).
So, if you are lucky, your area has been flown in the last 2-5 years at high resolution. If you are unlucky the imagery can be 10 years old and low resolution (or even worse, LANDSAT satellite imagery which has like 10 meter pixel resolution).