Hello and thanks for the clarification, i.e. just 2 people, a husband and wife - from the OP I believe a number of us were unclear as to the number of individuals involved, e.g. parents + kids which prompted recommendations to look into 'family sharing' - now that the number of users has been stated, the decision is somewhat easier. My wife & I share the same Apple ID (but have different iCloud accounts, so another decision to make) - having the same
appleid allows you to share purchases made (such as books and apps, saving $$ on dual buys of the same items) - thus, if we want to read the same book on our iPads, I'll purchase it on Books, otherwise I might use Amazon, just one example.
NOW, other items are shared that might be annoying or positive (such as a calendar or groceries list) - here's
ONE TAKE - there are plenty of other google discussions on this topic, if interested. If one of you obtains a new Apple ID, then previous purchases made on the other ID will not be available. SO, I agree w/
Ian; wife & I have been fine w/ the same ID. Dave