Like others have said, it really depends on your fitness. I'm using a 12-26(27?) that came with my bike and it works just fine until I can get an 11-23. I wouldn't say I'm just a recreational cyclist so I prefer the smaller cogs. There have been a handful of times though that I would've liked to have an 11 cog over 12. Some group rides can surge to 35+ and sometimes a leadout before a sprint, I would've liked to have that 11 cog available for use but it's not something that's holding back my riding.