A common question is, "How much gear do I need?" The answer is different for everyone, but here are a few things to think about.
What are the requirements for what I want to do? Your dojo has certain gear requirements, and if you want to participate in tournaments you need to follow their regulations as well. Some people wear dojo regulation gear regularly and then add to it for tournaments. I recommend wearing the same gear all the time so that your body is used to moving effectively while wearing it.
How easily to I bruise? The most common sparring injury is a simple bruise. Anything more serious than that is extremely rare. That being said, if you bruise easily you may want to wear some extra padding so that you can continue to train hard each week.
Wearing less gear does not make you look more tough! There's nothing wrong with wearing a little extra padding. In fact, it's the smart thing to do. Actually wearing a little extra gear (such as shin and/or forearm pads) is what you want if you plan to be tough. Wearing enough protection means that you can train harder without hurting yourself or others. Many of the people who follow this "less gear = more tough" mentality are extremely ineffective at an early age because their laundry list of injuries has finally caught up with them.
Don't overdo it. More and more types of protective gear are being invented each year. They have enough of it where you can look like the above pictured injury proof marshmallow person. This may be appealing especially if you bruise easily, but imagine trying to move quickly while wearing all that. Make sure your gear doesn't slow you down.