A few tips on the bike:
- Keep it in good condition. Not only does it last longer, but also run much smoother.
- Puncture resistant tire are a great invention.
- Lube that chain.
- A bell can be usefull
- Lights and reflectors!

A mountain bike isn;t the best in my opinion, unless your roads are really bad. As a bike commuter my self, my bike is a dedicated 'citybike'. Relatively heavy, but now maintenance and practical:
- Good fenders to keep you clean.
- Enclosed chain, keep the chain and you clean. Also prevents you from damaging pants in the cogs.
- Relatively thin tires (compared to a mtb that is), which rolls easily.
- Fixed lights front and back
- Cargo carrier at the back.
- I have a 3 speed internal hub gears. Which is low maintenance and inexpensive.
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