The most popular assumption is the estimated annual return rate on your investment portion is 8% or higher. In past 10 years, very few policy holders make it. So they are still paying the payment now although it has been 4+ years after they purchased the policy.
There are 2 reasons we buy insurance (JY101? has a good post about it) - To protect the love ones, buy term with enough coverage; To use is as shelter to defer/avoid investment income /estate tax, buy IUL. So if you have high income tax, maximize all other plans, plan to leave $2 mil+ to kids, then you should consider IUL.
