For a long time, a lot of brethren have organized or participated in “retreats,” a daylong or weekend series of meetings for men or women to teach, study, pray, visit, etc. This arrangement provided it is not a church-sponsored recreational event, is not wrong in and of itself. Paul used several occasions to teach the gospel outside of the worship assembly (Acts 18:11; 19:10; 20:31).
However, care needs to be exercised to make sure these times of “renewal” include “devotion” to sound doctrine. There seems to me to be a lot of neglect in strong, foundational lessons among brethren now. We do need to build ourselves up in the “most holy faith” (Jude 20), but please do not let these “retreats” of “renewal” ironically make you spiritually worse in the long run.