How long after you had an operation is it considered a pre existing condition? -

Forever. It's not the pre-existing that does you in, it's the "lapse in insurance coverage". As long as you have no lapse, it's not a problem. Once you let it lapse, you'll have to get your next health policy through a group employer, and wait out your 18 months of coverage until it becomes covered again. THEN you've got coverage for it. depends on your specific plan, what state you are in, what type of surgery etc. If you give me a bit more information I can probably help as I have been in medical insurance for 24yrs.