The recruitment of new members requires delicate secret steps by terrorist and extremist organisations. This vital organisational activity needs to be smart and effective, takes time, and can be discovered by security and intelligence services. This paper shows that recruitment is a flexible multi-tool process able to be smartly adapted to suit the circumstances, needs and character of targeted individuals. We test and confirm the hypothesis that al-Qaeda and ISIS have been flexible in their use of different models and approaches to recruit new members. Our assessment of recruitment activities in the case of selected terrorist cells confirms the same recruiters interchangeably use various recruitment models (Net, Funnel, Infection, Seed Crystal) and recruitment approaches (public and proximate, public and mediated, private and proximate, private and mediated). Such flexibility was not only detected over the longer time period, but also while recruiting members for individual terrorist cells.