John... the answer to that question depends upon many things. This list isn't complete but I'll try to start it, to give you some information to use in making your decision.
* If the bit has been overheated and burned in the process of dulling, then no.. as the crystalline grain structure has changed and it will not retain a good edge.
* Would you take it to someone to be sharpened ($), or do it yourself?
* If you take it to someone, what do they charge?
* What is the turnaround time? Do you want to wait?
* Do you enjoy such activities?
* Does the pleasure of sharpening your own bit exceed the time it takes you to do so?
* If you do it yourself, will doing so let you finish a cut (or project) that you might otherwise have to defer until you bought another?
As for myself I work full time and woodworking is my hobby. Sharpening my chisels and planes is rewarding when they glide through what I'm cutting but as hand tools you can feel that more. I do not find pleasure in sharpening machine bits. Therefore, if the bit is expensive I would have it resharpened; if its a $2 bit I would likely toss it. I don't know this for certain but I'm pretty sure that different folks will have a different sharpen / toss point, with some on either side of me.