There’s a mind boggling array of paraphernalia  available  for bikes and everyone has their own ideas about  what you need and what you don’t. I like to keep things simple, but even so, there's a few things I need in order to maintain the level of safety, comfort and reliablity I need to be happy.

Riding a bicycle is fun and is good for you, but it's not without hazard and you’re safety is in no way guaranteed. Besides being aware that you are at risk and riding accordingly, use of some of this equipment will do much to put the odds more in your favor.

I recommend that you don’t leave your driveway without these:

Helmet
If there's ever just one time that your head hits the pavement, I hope  you have yours on. Wear a helmet, it could save the life of someone you love.

Riding Gloves

If you fall you’ll put your hands out to catch yourself. Whether you’re on pavement or gravel, your hands won’t like it a bit. Fingerless gloves with mesh backs and leather covered padded palms are a good choice. Full fingered gloves offer more protection but it’s your palms that usually get the most abuse.

Rearview Mirror
You need to know what’s behind you at all times so you can get out of  the way. Not knowing what's bearing down on you is going too far in putting your fate in the hands of unknown others. 

Taillight
To stay alive, you need to be seen. Even in broad daylight bicycles are hard for motorists to notice.  Most effective taillights are small, light and  use led’s that blink in sequences designed to be noticed. Due to the led's, small batteries last a very long time. A  good tail light significantly increases your chance of not being run over.

Those, in my opinion, are a must, the least you can do to protect yourself. The helmet looks goofy, the mirror takes getting used to and the tailight needs a battery every know and then. The gloves are no problem.
Headlight
If you ride at night you need a headlight to see and more important, to be seen. Even when you're on the road during daylight, a flashing green or amber LED  light on the  frontdramaticaly increases your visibility. 

Taking care of your bike before you leave home will prevent most mechanical problems,
but breakdowns usually don’t occur in your driveway. Ten miles from home, in the rain, is more like it. Pack these in a seat bag and keep it on your bike.

Folding multi tool
To adjust the seat, handlebars and  tighten things when they come loose, and you don't want to walk home.

Tire Gauge
A must-proper tire pressure is essential for a safe ride and to avoid flats.

Spare Tube
Flats happen. Most of the time it's a puncture and can be patched, but sometimes it can't. It’s easier and quicker to replace the tube than it is to patch it, especially on the road or trail. If you don't pack the tube at least carry a patch kit.

Tube Repair Kit
Smaller and easier to pack than a tube. You need this for when you have a second flat fifteen minutes after having replaced the tube. The self adhesive kind are easy to use and come in a very tiny box. Tire levers should be in the kit.

Air Pump
You need air. A small hand pump works well and fits in the seat bag. CO 2 cartridge pumps are even easier to use- unless you run out of cartridges.

Seat Bag
Fastens to the bottom of your seat and holds all of the above in a neat little pack under your seat. The expandable type open up enough to stuff a few other odds & ends in when you need to. Most have a place to clip your tail light to.

To enhance your ride

Water bottle
If you ride, you’ll get thirsty, if you don't, you're not riding enough.

Rear Rack
Fastens above the rear wheel and provides a platform to fasten your stuff to. It also doubles as a fender to keep road spray off  of your back.

Bungee Cords
To fasten your stuff to the rack. Put jacket, bread, cheese, wine in a small duffel bag and bungee it to your rack.

Tail Trunk Bag
A square pack that fastens to the rear rack, usually padded, with a zip open lid. Some are expandable and can hold a lot of stuff. Good for cameras, wine, cheese...

Speedometer
Looks like a large watch and fastens to the handlebars. Keep tabs on your speed, mileage, trip distance, riding time, average speed, top speed & the time. It can, however, be disappointing to have proof that what felt like five miles was only one.

Chain Cleaner & Lube
A clean chain lasts longer, makes for easier pedaling and smooth shifting. Doing it yourself gives your bike a chance to bond with you. Not too many dollars gets you a device that makes it quick and painless.

There are accessories for every conceivable purpose. I try to stock the ones I find to be simple, reliable and useful. For prices and descriptions please see the Accessory Price List.