There is a statutory obligation to file an Affidavit of Means, discovery will generally be sought in family law matters where it is considered that there are defects or omissions.
There are time limts.
Also in Ak v PK [2005] IEHC 331 an unsigned undated list requiring 34 items - the Master said "No relevance, no reason, no necessity - no discovery' i.e. no fishing trips.
@WN4 the summary would seem to be if you ask for the kitchen sink that will be viewed as a fishing trip. If you knew there was a certain bank account and it does not appear then that might be grounds for the discovery. Its not scientific I think you have to have a reasonable basis and its not a terribly high standard. Feel free to give us details apart from the parties.