A bad client can cost you more than just the time spent dealing with the hassle they create. There are greater risks like not getting paid, or having legal issues. I have a strong gut feeling when dealing with a bad client, and every time I’ve ignored it, it’s ended badly. Over time I learned to recognise the things they did leading up to a bad break-up.
Whether you are just starting off your freelance career or have been in this field for a few months, marketing yourself and your brand is one of the most important aspects of your business. No matter how good of a designer, graphic artist, etc. if you don’t know how to properly market yourself your business won’t grow.