Despite the vast body of research on charitable giving and its drivers, no research has investigated the longitudinal dynamics of individual donation decisions. We analyzed unique data with nearly 300,000 real donation decisions made by more than 20,000 individuals for a period of 10 months. Each decision entailed a choice of what to do with money received for completing a survey (on average, €0.67 per survey): keep it or donate to charity. We found that most of the participants (89%) always chose to keep the money. Within the group of people who sometimes kept and sometimes donated the money (that is, Switchers), we find that people do not change their decision very often (cf. moral consistency). However, the likelihood of donating increases when people kept the money the previous time, and the amount at stake differs substantially (both positively and negatively). Finally, once Switchers donated, they are more likely to keep the money next time if they can earn more (for example, €2 now versus €0.50 last time), signaling moral compensation. These longitudinal data provide a first step to better understand charity donation decisions, not only in terms of a more nuanced description of decision-makers but also in terms of the dynamics of charity donations.