DON’T work for free
This may sound a little weird, but your former employer can actually benefit from you quitting your job. Let’s say you are a nice person who enjoyed your job, but it didn’t work out (for whatever reason). You take all the right actions by leaving instructions for another to take over your clients, and leave on good terms. Whatever you do – do not fall into the guilt trap of doing work for free. You may think you would never do so, but you wouldn’t believe how many people take time out of their new schedules to finish up projects/tasks at a former job. It doesn’t matter how much you liked your last boss, they should not contact you to square things away beyond your departure date. This is why you gave the proper notice and worked diligently to finish up your work. Anything left over is for the new hire.