Does company policy vary from company to company regarding the number of months after the initial activation of the policy (ie E 12 months, 24 months, Zero months...etc) that a claim can be made for a condition not originally made known on the application?

I'ver heard about an "incontestible period" (Federal Law(?) where-as an applicant can make a claim for a pre-exisiting condition after 24 months of coverage even though it wasn't listed on the original application or made known to the insurer.

Is there any truth (or variations) to the above? Does it vary from company to company or is it all just considered insurance fraud?

Please advise?

Thanks!