Do You Need a Cover Letter for an Hourly Job?
Usually no, sometimes yes, and there is one situation where it does more work than your resume does.
Most advice about cover letters is written for salaried office jobs, which is why it feels so far away from an application for a shift at a warehouse or a clinic. The honest answer for hourly work is that a cover letter is optional most of the time and genuinely useful some of the time.
When you can skip it
If the application is a form with no upload field for one, skip it. If the posting does not ask for one and your experience lines up cleanly with what they want, skip it. Nobody has ever been rejected from a stocking job for not attaching a letter, and a generic one that says you are a hard worker and a team player adds nothing.
A weak cover letter is worse than no cover letter, because it takes up a reader's time and tells them nothing they could not already see.
When it is worth the ten minutes
Write one when something about your application needs explaining before they get to it. Switching industries, coming back after time away, applying somewhere out of state, or having a history that looks scattered until somebody tells you why. In all of those, the resume raises a question and the letter answers it in four sentences.
Also write one when the posting asks for it. That request is often a filter, and it is a cheap filter to pass when most applicants skip it.
What to actually put in it
Four short paragraphs, on one page, and never longer. Which job you are applying for and where you saw it. What you have done that matches the main thing they asked for, with one concrete example. The thing that needed explaining, said once, without apology. Then how to reach you.
Use the posting's own words for the work. If they call it patient care, do not call it caregiving. Matching their language is not a trick, it is how you make it easy for a busy person to see that you are the thing they were looking for.
Address it to a person if you can find one
A store manager's name is often on the door, in the posting, or on the company page. "Dear Ms. Whitfield" reads like someone who did five minutes of work. "To Whom It May Concern" reads like a form letter, because it is one.
If there is genuinely no name to find, "Dear Hiring Manager" is fine and nobody holds it against you.