This is my favorite answer because while I am definitely not a welder, I do believe that experience is the best teacher. For me, welding is not likely to be much more than a hobby, but I think it is nice to be able to make my own repairs or "build it myself" without having to pay someone else to do it for me. I just prefer to "do it" myself, regardless of what "it" happens to be.
When I originally asked my question, I thought it would be fun to see what kind of responses I got but have to comment on the responses that said "Being certified or paid to weld" and equate it to people being licensed to drive. How many "licensed" drivers are there on the road today who probably shouldn't be driving? Same thing applies to being "certified" or "paid" to weld, or to do anything else.
Personally, I like to be self-sufficient by knowing how to do a variety of things (welding, etc...) myself but when I see people who have not even picked up a screwdriver in their life, I think it is a sad thing to see.