Potential clients can only assume that if you are sloppy with simple things like spelling and grammar that your work is as bad if not worse. Consider this scen

Potential clients can only assume that if you are sloppy with simple things like spelling and grammar that your work is as bad if not worse. Consider this scenario: You take your car to a mechanic to get fixed. When you get the car back, there are oily finger prints on the hood and fender. The steering wheel is sticky and there is dust on the dashboard. Most people will have concerns about the quality of the work done. It's the same with all professions. Your potential client probably knows little about the technical aspects of your work, so they will judge you on the basis of things that they can observe and understand.