The amount of time your health insurance will stay active after leaving a job depends on a few factors, including whether you have COBRA coverage, how long your job provided health insurance, and whether you have another source of health insurance lined up.
If you have COBRA coverage, your health insurance will stay active for 18-36 months after leaving your job, depending on your circumstances. COBRA is a federally-mandated program that allows you to continue your employer-sponsored health insurance after leaving your job, but you have to pay the full premium yourself.
If you don't have COBRA coverage, your health insurance will usually only stay active for a few weeks or months after leaving your job. However, your job may have provided health insurance for a certain period of time after leaving (e.g. 6 months), so you should check your policy to see how long it is active for.
If you have another source of health insurance lined up (e.g. you're going on your spouse's health insurance), your health insurance will usually stop being active as soon as the new policy starts.
So, in summary, the amount of time your health insurance will stay active after leaving a job depends on a few factors, including whether you have COBRA coverage, how long your job provided health insurance, and whether you have another source of health insurance lined up.