Each inventory is a customer service depending on what the homeowner feels is of value. Focus on the high value items first to ensure the details are captured. Also, it is very common to do group entries for certain items such as linen closets, kitchen cabinet contents, CDs, DVDs etc.... By making one entry with a description for the lot you can save a ton of time.
Many inventory service providers put together a one page sheet listing the types of items they do as a group to save time, you can present to the homeowner initially and if they have any objections they can let you know so I more detailed inventory is done.
