A study which looked at 27 different negative health effects of binding found that some do not show for years.
A survey  of 1800 females who used breast binders reported a number of negative health effects which develop over time. Some of these effects are felt immediately. However, in other cases, it can take years for the negative health effects to be fully seen:
 Peitzmeier, S.M., Silberholz, J., Gardner, I.H., Weinand, J. & Acevedo, K. (2021). Time to First Onset of Chest Binding-Related Symptoms in Transgender Youth. Pediatrics 147 (3). [Link]