I never do overall final sharpening until the photo is actually at its final output size. I do selective sharpening of things like eyes prior that stage however. To make things consistent, if I'm going to web, I always use the same method of creating the final output file and that method does a stair step reduction in size (reducing it in size incrementally down by a small percent each time until it reaches the target size). In between each step a very small sharpening phase is completed. This is all an automated process of a plug-in that I bought some time ago. I really like the results.
If I don't know what the final output will be (print or web, or the size), then I forgo the overall sharpening. Since I shoot in RAW, that means I have to turn off the sharpening that the RAW converter might do. Fortunately with ACR, you can have it turn off the sharpening, but still show the image visually with the sharpening while in the RAW converter. If you shoot JPG, then you don't have this luxury. No matter what sharpen setting you use in the camera, some sharpening is always done.
"The map is not the Territory"