Informal financial services (IFSs) provide various types of investment avenues for both rural and urban populations in Zambia. This paper is a critical review of the sustainability of various informal investment typologies Zambians has been using and adopting to increase their financial resources and solve their livelihoods and social issues in the process. An evaluation of why people and organizations opt for specific financial services that come in the form of savings and lending groups will be discussed in detail to understand if they have been meeting people's expectations. The paper derives its data from various studies in the past 10 years that emanates from Zambia and Sub-Saharan Africa. While the sustainability of various typologies of informal financial services is broad, they are measured through risks associated, savings policies adopted, group loan guarantees and flexibility, interest and transactional expenses enforcement, income-generating, wealth creation and any social capital investment. The research reveals that limited studies have looked at various typologies of savings and lending groups, including evaluating their sustainability. This study helps in decision making for anyone or organization who would want to join or start a savings group in Zambia and key parameters to follow.