A few inexpensive pieces of kit will make sure that your bike commutes remain simple and stress-free.
You don't need to spend your life's savings down at the bike shop either. British Cycling Ride Membership saves you money on the essentials and this is all you really need:
Waterproofs - for those surprisingly rare days when you get caught in a downpour. Look for breathable fabrics so you don't get that 'boil in the bag' effect. More
Toolkit - Pump, innertube, tyre levers, folding Allen key set
Bag - rucksack, courier bag, shoulder bag, panniers - whatever suits your style, bike or budget. More
Lights - if you commute in the dark you'll need a set of lights. Good news is that quality lights are cheap, lightweight, unobtrusive and readily available. More
Helmet - Although not a legal requirement, we recommend wearing a good quality, well-fitted helmet to afford some protection in the event of a fall. More
That's it. Simple.