Not sure why you would need to know what the expenses are if your client is on a gross lease, but the only real way is to ask the Landlord what the expenses are running. You cannot just estimate them since they are very different in every state. The other answer given talks about snow removal, but if the proeprty is in a state like CA than you don't have to deal with that, but you may have to deal with parking lot attendants or valet, security guards, etc. and you cannot guess on what these expenses are.
Dec 28, 2009