Does Iran need 24 days to stash its nuclear program before an inspection?

NY Times:

Verification Process in Iran Deal Is Questioned by Some Experts

Some experts have expressed skepticism over a provision in the nuclear accord that gives Iran 24 days to grant inspectors access to suspicious sites.

There is a reason why in some cases you need no knock warrants.  It is a way to find the evidence before it can be destroyed or flushed down a toilet,  Iran has a long history of cheating and lying.  Is there any reason to think they will change their conduct because they have signed some papers?   Common sense, which is in short supply in the Obama administration tells you that 24 days gives Iran a lot of time to hide or destroy evidence.  It is just another aspect of a very bad deal.

On top of that the US will be funding Iran's terror operations with the windfall it is giving the Iranians and is trying to counter that by providing more defense assistance to US allies in the Middle East.  This puts the US in the position of funding both sides of a bloody war in the region that will be caused by this agreement.