I've been working in the electrical industry for over 25 years. I've encountered many different things that have made me cringe. I'm always coming across wiring that has been done either by a homeowner or an inexperienced electrician. From wiring that is sloppy or used improperly to too many wires in a junction box. It's usually very easy to identify.
It maybe that the homeowner is wanting to save money so they tackle the job themselves. The homeowner may turn to the internet or youtube for incomplete information, but it takes an electrician 5 years of training to understand all the intricate details of electrical wiring.
It takes alot of experience and skill to be a great electrician.
If a fire were to start as a result of DIY wiring that wasn't inspected by ESA, your house insurance would deny your claim. Don't risk your family's safety just to save a few dollars. Your home is probably going to be the most expensive investment you will ever make. Hire a Licensed Electrical Contractor.
During the Christmas holidays I visited my cousin that had recently purchased a new home. When he did the home inspection everything looked fine. It wasn't until he moved in and was putting dishes in the cupboards that he noticed this.