Re: Drag on a fly reel
For me personally, it's when I get a hot fish on. You will know. A fish on the reel, will put itself on alot of times. Size of the fish, current, the aggression the fish uses to escape, all become a factor. If you're hand stripping a fish in and it gets "hot" on you, try to control your fly line as the fish is running with it until your near the end of the excess line. Then, wind up on the reel. Make sure you're layering the line evenly by using your index finger to put it on the reel. Line bunched to one side of your reel spool will cause many problems. Honestly, this will all become natural as you grow to the sport.
It's all in how you hold your lower lip...