I'll be applying to many different jobs and am wondering if not doing cover letters will hinder my chances at getting a job.
Real: If depends. If you are filling in an application form, a cover letter is generally considered non-essential. However, if you are sending in your CV, I would strongly recommend that you send a cover letter as well, making it clear what job you are applying for and why you think you'd be good at it (what relevant qualifications/experience you have). This is because a CV is very general and a cover letter helps to demonstrate your interest in and understanding of the particular job/company you are applying for/to.
Best to include a cover letter
not many companies these days care about cover letters + the resumes that are submitted are "read" by computers that are looking for key words
No it is just a summary of how good you think you are and employers cannot be bothered to read them.