First and foremost, I am not a financial advisor. Do not take this as financial advice… HAHA
For us, it’s still too early for us to reap the benefits. we're only 40 and we started them about 4 years ago so it's gonna take some time until it becomes worth it. It is part of our long-term strategy though. The plan is to have the cash value grow tax deferred at a fixed rate, then later in life be able to tap into it (loan) without having to pay penalties or taxes, then the death benefit will cover the taxes and loan (provided you leave money in the policy to keep it active). but again, we have term policies so we're not reliant on the whole life policies for coverage (any outstanding loan is paid through the benefit, meaning the benefit is lower).
as to your questions
you can get a policy that gets "paid off" early, like 15 or 20 years. but the way it's set up is that if you can't pay for an amount of time, the cash value funds it.
as to how it grows, think about it as a home loan amortization schedule.the policy payment is front loaded and your cash value grows bigger the longer you keep it.
you can surrender the policy (bad), withdrawal from the cash value (tax free only on the cash value up to what you've paid in), and loan (what
@s1uggo72 was talking about which MY UNDERSTANDING is that you can take as much loan against the value as you want, and you aren't hit with any taxes or fees provided you keep the policy open and continue paying the premiums. when you die, the death benefit covers the fees and taxes)