Nobody owns your time but you, so you don't have to tell anyone anything you don't need to

I differ. I see no harm in telling. Yes your time is yours, but think it is common courtesy

You can let them know that you can only work certain hours and days, keep your calendar organized

This used to be known as “moonlighting”. Most employers allow it. The need for many people to hold a second job just to make ends meet is an unfortunate reality of today’s economy. However, I would suggest you read your employee handbook or talk to your supervisor and be up front with it. Fatigue and distraction caused by long hours from holding a second job can reduce productivity and raise safety concerns. Additionally, if it’s a conflict of interest, you could jeopardize your main source of income as that would be grounds for dismissal. As long as it doesn’t spill over into any of these areas, as they are the common areas of concern for an employer, you should be fine with keeping your 2nd source of income. Good luck!

Check your HR Policy for "Outside Employment" disclosure requirements.

Grace, reading what you just wrote about your second job sounds to me like you just can't wait to let someone dump on you. Second schmencond ! - are you working less efficient at your first job, or are you slacking in general. If you were spending your "second job hours" writing a book, working out, or babysitting, would you feel you are somehow obligated to tell your first employer how you spend your time. Perhaps if you're working as a waitress where your boss likes to go for dinner, you could prepare/think about what a fun encounter you could have. Otherwise, grow up. You're not cheating on a math test in fifth grade. Are you as concerned about telling your second employer that you have a "first" job? Learn how to deserve/ask for a raise or promotion - then maybe you won't need that second job. Or perhaps you might love a life-chance - commonly known as "a different "first" job". Go forth and prosper.

Ok

Great question! I think as long as it doesnt interfere with your other jobs, you don't have to disclose the information.

DO NOT TELL THEM UNLESS YOU HAVE TO BECAUSE I WAS BEING COURTEOUS TO MY NEW EMPLOYER BY TELLING THEM I WAS GOING TO BE WORKING AT MY OLD JOB AGAIN AND HAD IT ALL FIGURED OUT TO WHERE IT WOULD NOT INTERFERE WHATS SO EVER AND THE NEW EMPLOYER GOT MAD AND LET ME GO SAYING THAT THEY WOULDNT BE ABLE TO UTILIZE ME THE WAY THEY NEEDED WHEN I HAD ALREADY BEEN WORKING THERE AND WAS HIRED AS FULL TIME 40+ hours but never even got 30 and it was only $10 an hour!

You do not have to tell your boss unless there is a conflict of interest, like for example the second job is with a direct competitor of your employer