How do you sharpen saw blades?

I really depends on what type of saw you are talking about. Generally circular saw blades are simply replaced. Larger blades for that of a chop saw and table saw can re professionally sharpened by any number of specialty stores. This is all a matter of what blade you are talking about.

Yep, we got to know chain saw, hacksaw, circulare saw or what. Most average DIYers are better off buying a new blade or having a shop do the work.