When the evening rise is going well there are a lot of fish coming up, and it is possible to hook a fair number of them. This inevitably leads to damaged leader and blunt hooks. Bust offs and losing fish due to dull hooks happens, and when it does happen it is frustrating to be spending too much time tying new flies onto the leader.
This is where the Smith Creek Rig Keeper makes a huge difference.
Having dry & emerger rigs pre tied means that in the low light of the rise you can replace a rig quickly and easily with one knot rather than attempting to tie two or three. I usually carry six mayfly and two caddis rigs, though it is very rare for me to run into a caddis hatch.
There are few products I believe should be compulsory for fly fishermen because there is so much diversity in the way we fish. The Smith Creek Rig Keeper should be compulsory for anyone who uses a two fly set up, as it saves so much time when changing or replacing flies.