If the piece is very light weight and I can carve it with my thumbnail , I stabilize it . It is possible to handle that kind of piece with multiple applications of thin CA , turning down the thin layer of hardened material after each application , but the wreck rate will be larger unless you are extremely careful .
Pieces which are easily thumbnail dented but not carveable can usually be successfully turned with sharp tools . Sharp defined as being able to shave hair off the back of your hand with it .
You may also encounter pieces which are basically hard , but have small areas of thumbnail carveable or dentable material . Those I harden with thin CA .
That is my approach , but I sometimes punish myself with challenges . Others don`t want the challenge so they stabilize everything that can be scratched , or they stabilize because they feel that the end user shouldn`t have to worry about the pen getting scratched in use .
You have to decide which approach you want to take . The main thing is to have fun , and treat the inevitable failures as learning experiences . Someone will always be available here to try to help .