Originally Posted by genec
That two bike two everything situation is what I have... but I do it a bit differently. One bike is the commuter, and it has all the bells and whistles... and redundant, redundant lighting. Racks, bags, you name it.
The other bike is my "true" road bike and it has just what it needs to fix a flat and that is about it. No lights, no mirrors, nothing extra.
I enjoy each bike for different reasons.
My situation as well... except I now have 3 bikes. I've got the short distance commuter fixie. I've got the long distance commuter (road bike geared down a bit and with racks, panniers and permanent fenders). I've got the stripped down road bike. Road bike and long distance commuter share the saddle bag with tools and flat fixings, and the pump. Fixie has it's own tool bag since I need to tote around a box end wrench to get the wheel off. Fixie and commuter share a niterider light, but each has its own blinkies (or used to before one fell off and was run over; got to get that replaced.
The problem with cycling is I always want another bike. I got the fixie not even a year ago and I'm already forming long term plans for another bike. Have to decide where I want to take this cycling thing. It will either be a better quality road bike (it's always nice to have a rain bike) - which will suit my ideas of getting into centuries or racing; or it will be a touring bike so I can take a week to ride around and not have to answer to anyone but myself... decisions, decision... but I digress.
Rule of thumb I have is that expensive and universal stuff (headlight, multitool, spare tubes, frame pump etc.) I share between bikes. Unique or inexpensive things I buy redundent. Beyond that, I buy redundent if there is a chance I will stash the bike at work permanently; for instance my fixie, during the summer, will probably be stashed at work since most of my commuting will be with my long distance commuter. Because of this, the fixie gets it's own repair kit.