Reed making techniques are the same now as they were when I started making reeds in 1991. It was the same 100 years before that, and it will be the same 100 years in the future.
The materials and the design of a chanter reed may have changed a little, but the basics are the same. If your reed is too hard, material must be removed to allow for easier vibration. If your F is too flat the reed mouth is too big. If you have a sharp high G, thin the tips and so on.
Ridge-cut reeds were introduced in the 70s and the techniques for adjusting these reeds are slightly different than for the more traditional straight-cut reeds, but basic the principles are the same. One thing has changed and that is the tools – sandpaper, blades, etc. Modern tools are much better than in the past and make the job much easier.
Is it ever ok to return a reed?
Yes, it is. But only sometimes. Remember that reed makers depend on your continued custom so none will deliberately send out a reed of poor quality. However, problems do occur from time to time. Sometimes reeds are damaged in the post, or during transit the cane decides to split for no particular reason. Always check your reed immediately when it arrives. Look for splits along the length of the tongue and chips along the top. If you see either of these impairments the reed should immediately be sent back for replacement. There really is no other reason to return a reed. Strength is a very subjective matter and soft to one piper may be super hard for another. An exception to this is if you have ordered a reed set to an exact strength and what you receive is widely out. If you ever have questions or comments, contact your reed maker.