First deal and wondering when review of leases should be?

[Mick Patel]

looking at a property in NJ.  I've settled on an offer amount to submit. but I'm not really sure when leases should be reviewed? should I expect them during DD or before making the offer?  if its during DD, what happens if I just don't like the contracts/expirations, or my ability adjust rents? Can this be a reason for refusing the deal?