Non-operative management (NOM) of simple acute appendicitis and appendix mass have been well reported in children. Following initial NOM, ongoing management strategy involves either elective interval appendicectomy or expectant management. This chapter explores existing literature regarding indications, risks and benefits of interval appendectomy compared to expectant management. A literature search was conducted using PubMed, Embase and Cochrane central on 30th January 2023 to identify studies comparing interval appendicectomy to expectant management after acute appendicitis in children. Outcomes included recurrent appendicitis, healthcare costs and quality of life. Recurrent appendicitis following NOM of appendix mass was reported to occur in 8–12% of children, whilst this was 4–24% following NOM of simple appendicitis. One randomised controlled trial (RCT) found that 6% of children undergoing interval appendicectomy, after NOM of appendix mass, developed a significant post-operative complication. Healthcare costs vary by region. A UK study found similar costs for emergency and elective interval appendectomy following NOM of appendix mass. A US based study found elective interval appendicectomy to be less expensive than an unplanned admission due to recurrent appendicitis. A UK based RCT, the CHINA study, demonstrated significantly lower costs of expectant management versus interval appendicectomy for appendix mass. Limited data were identified reporting quality of life. These data are reassuring and generally do not support interval appendicectomy following NOM of simple appendicitis or appendix mass in asymptomatic children. Importantly, both treatment options should be disclosed to parents and children. Further research on quality of life and long-term outcomes are essential.