The server also needs to state in his affidavit the complete address of service for the defendant. Interrogatories are a helpful tool for discovery.Interrogatories are written questions which focus on any information relevant to the case. NOTICE OF HEARING (new). When a Party May Serve Interrogatories. A party may propound interrogatories at any point up to thirty (30) days before the end of the discovery period. Service is "the formal delivery of a writ, summons, or other legal process or notice" according to Black's Law Dictionary. Timing. Due Date for Responses ; Discovery Rules. Summons to Appear to Complete Juror Qualification Form, Jury Forms. In general, Texas has very few official legal forms.