All projects that you decide to carry out will carry with them an inherent risk. It is therefore your choice to run the risk and do the project yourself or pay someone else to run the risk in your stead.
Rigging is an excellent example of a risky activity where safety is important. There are two main concerns while aloft: falling, and getting hit.
Falling is an obvious one. If you go to the top of the mast and your rope breaks, you will plummet to the deck and probably your death. This obvious safety concern gives me employment as other people pay me to go up their mast to carry out simple tasks high up in the air.
The other safety concern is much less obvious. Getting hit is a major issue that will cause serious harm to a person who is aloft. The biggest cause of these injuries is hitting the mast itself. When working aloft, all movement of the boat is amplified as you go higher up the mast. A simple wake that rolls the boat at deck level will send you swinging far from the mast while aloft. The problem is when you swing back, you will smash into the mast with a lot of force and no protection from the impact.
To mitigate this risk, a safety line is tied to the spar, preventing you from swinging far and minimizing the harm caused by swinging away and back into the spar.
Safety became very apparent to me when I started casting bronze for the dinghy we are building.
My original safety gear was a pair of fire proof gloves and some long tongs to extend my reach into the hot and molten metals. Aside from the gloves, I had no other safety equipment. After much disdain from my parents, wife, and other people on the internet, I decided that it would be wise to cover up and be protected.
I was viewing casting bronze as I view target shooting. If you mess up, it can kill you, so pay attention to what you are doing and don't mess up.
My main concern was burning myself, so I donned fire proof gloves. I know that the bronze is close to 2000*F and would burn through my skin in a heart beat. Instead of donning fire proof clothing as well, my plan was to not put it over myself.
When target shooting, you wear ear protection and aim the gun away from yourself. I have never worn a bullet proof vest while shooting at a range because I never plan on getting shot while there. Likewise, I was not wearing flame retardant clothing because I was not planning on setting myself on fire.
Just like with guns, one slip can have costly consequences, and so I have acquired the appropriate clothing to wear while doing my last attempt at casting.
Safety is important and you never plan to get hurt. I have been very lucky on my first two attempts at casting. Hopefully my luck continues on this third and final attempt at casting while I wear protective clothing.