Gear keeps you warm and protects you from bad conditions! It has two main purposes: protection and comfort. Protection reduces your damage in an accident. Comfort is part of safety because discomfort is distraction and distraction causes accidents. Remember, any fool can be wet, cold and miserable.
Why buy gear?
When you buy a motorcycle you save money, as there is less to a bike than a car, e.g. two wheels instead of four. So put back some of the money you saved into buying riding gear. A car has a metal protective shell, but a bike does not. Compensate for the lack of vehicle protection by buying body protection. Say for $6,000 you can buy a bike that is equivalent in age and miles to a $12,000 car. Why not spend 20% of the money saved on safety gear, i.e. about $1,200? Buying body protection is just common sense.
My protection in order of priority is
Riding without any personal protection is a false economy that will cost you in the long run. Riding without a helmet is suicidal, as the head is so fragile. Riding without a jacket is dangerous because it protects you the most. Riding without gloves or boots is careless, because hands and feet are easily hurt. Riding without leggings is unwise, because roads are dirty, dusty places. You decide your level of protection.
The purpose of gear is not just to protect you in an accident but also to provide the comfort to make good decisions. Being cold, wet or uncomfortable distracts you from riding safely. Without a helmet, face and eyes are battered by wind and rain. Without a jacket, clothes flap and slap and get soaked in the rain. Without gloves, wind chill and bug splat affects your hands. Without boots or leggings, stones from the cars ahead strike your legs and feet. Good gear insulates you from the chaos. It gives you a peaceful place to make the right decisions when riding.