1. Enlist at the same time
- Onf for example all enlist at the same time and will quickly back after that as a complete group but the members will have no opportunity to do solo activity during that time like most groups do.
- Exo for example and a lot more groups. Members will going one by one according to their age. They have time to go for solo activities during this time but it takes longer for the group to be complete.
3. Enlist one by one in a short time after their solo activities
- Bts for example where they all released their own album and doing their individual schedules before enlist one by one close to each other. They don't really have much time so their solo promotion is quite short and rush but they will complete as a group faster.
My opinion, I like onf style better. Everyone go and everyone back together. The second one taking a lot of time even when I actually enjoy their solo promotion while the third options is really limited to groups with huge fanbase only and maybe only suitable for Bts bc it's hard for fans to support everything in one time.