The main reason people want to do the work themselves is because of the high cost of metal roofing pricing and labor. Hiring a person who is trained to do the job means that they have a great deal of skill and expertise in that field. They set their fees based on their level of training as well as the time they actually spend working for you.
Another reason that some people feel they would be able to tackle a 'do it yourself' task like metal roof installation is that many manufacturers include detailed instructions with their materials. One retailer even claims that he has given instructions to married couples who have not only completed their roofing projects, but "are still married"! He, of course, is referring to a couple who had such explicit instructions, they did not feel the need to argue over the project.
There is much concern over dishonest persons that have been taking advantage of individuals across the nation. Such persons will present themselves as professionals, and give an official looking proposal to do your repairs. Should you agree to the price, they claim to need money "to pay for supplies". They will then disappear before work has even begun. If you have any doubts, consult with a professional organization or the local better business bureau.
Hiring a contractor can be beneficial for many reasons. First, he will have expert knowledge of the intended project. Most likely, the costly errors that occur most frequently with persons who decide to do a project themselves will not be encountered by a licensed contractor. In addition, he will most probably be aware of all metal roof installation requirements and regulations that must be met, not only to successfully pass inspections, but also to offer a quality product. Finally, he should be capable of completing the job efficiently and minimize the incurred cost of labor and materials.
Finally, if upon completion, there are any issues with the roof, a metal roofing contractor will know how to remedy the situation. If one does the roof himself, chances are the mistake and all the costs associated with that mistake are going to be his.