A bicycle is a simple machine. Don't try to make this too complicated. Two important things to consider:
1. Bicycles, like shoes, come in sizes. How you fit on your bicycle affects your comfort, performance and enjoyment every single minute that you're on it. Nothing else even comes close in terms of importance.
2. Where is your bike going to live when you're not riding it? Do you have a secure place to park it while you are at work? Nothing worse than getting off work and discovering the bike that you were planning to ride home, is gone.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.