Now i'm sure we're all guilty of using repel when you simply cannot be bothered with wild pokémon. But do you ever consider what you are missing out on by using repel. By encountering less wild pokemon you are obviously going to encounter less shiny pokemon and are less likely to get the pokérus.
This came to my attention the other day as i was training a few pokemon and i thought to myself "I've been encountering a lot of wild pokémon, statistically i should find a shiny soon i reckon." BAM!! My next pokémon was a shiny, it was a hoothoot, but it was shiny none the less.
So has this thread changed your opinion on using repel? I personally now only use repel in caves and while surfing as i don't think i'll be too bothered if i miss out on a shiny zubat, or a shiny magikarp.