I thought I had answered this earlier. Perhaps I do so elsewhere. The main consideration is the size of tooth that lends itself to be sharpened. I think most people have difficulty sharpening teeth smaller than 16 TPI and so the best TPI for a tenon or dovetail saw would be 15-16 TPI. It is handy having a smaller toothed saw and you cannot go wrong with a 24TPI Zona Model saw. This saw keeps sharp for a long time. I have one that OI have used for three years but of course cuts quite small and so will not do what larger tenon saws will do, but you will be amazed at this little saw’s cutting capacity and cleanness of cut. No other saw comes close. It cuts on pull strokes which of course is backwards to me so I jerk it out turn it end for end and put it back. Veritas does make a 20 TPI dovetail saw, which I like and it cuts really well. Nice to have and keep it only for fine work.