Have you ever asked yourself the question: "Should I purchase standard software for my medium-sized company, or should I leverage my employees' expertise to customize an open-source CRM-ERP system specifically for my business?" Nadine Tomaschek addresses this question in the present study. The comparison of theoretical decision-making processes with practical applicability plays a central role. Additionally, the advantages and disadvantages of implementing the open-source system 'Adempiere' for the exemplary medium-sized IT service provider are explained.