Enumerating vs valuating property

If an SA is signed, is it acceptable to just enumerate/identify property without valuating it? Establishing mkt value for
many things would be time consuming or expensive (appraisals). Or, at least for valuable items ,(cars, jewelry,antiques,etc)
is it best to valuate them in case the divorce ended up in litigation? Once an SA is signed, and distribution of property is agreed to, can either party contest or modify the agreement successfully?

                                                                                                                                  Thanks

The agreement cannot be modified once signed. Valuation is the in best interest of the parties to ensure the agreement is fair and in the best interest of both parties. You do not have to have any official appraisals done if both parties can agree on what the value of any given asset is.