Simplifying a formula with multiple checks for User Input
I have a grid in which there are multiple line items (approx. 25). These line items are user inputs and when the user enters these either manually or through file upload, he sees a validation message that checks his input related to multiple conditions (e.g. Invalid Date, Mandatory Field Blank, Duplicate Entry etc.) . There are also some conditions that are derived from the combination of two user inputs. I am looking for some way (maybe like a lookup table or something) so that it's easier to maintain and update the formula if required. I do not want the formula to contain so many if-else statements + if else combinations. Can anyone suggest how can I simplify this?