My rule of thumb is.....
Cold water....slow retrieve/minimal movement
Warm water..faster retrieve/aggressive movement
Cold...I tend to choose (especially sinking) flies that match those conditions..I do NOT want a sinking fly that sinks rapidly in cold water, so I use very lightly weighted, or unweighted flies in early season & I refrain from fluorocarbon leaders until the water warms. I also like small foam beetles, etc & VERY seldom move them.
Warm..I will use a longer & quicker strip & LOVE to really RIP a strip using a sneaky pete or diver for bass. Gurglers work well in summer too.
There are always exceptions, but the above works for me...most of the time. NO rule is 100%.
Mike
FAOL..All about caring, sharing, & good friends!!