Redraft leagues are the most commonly played type of fantasy football. These leagues feature entirely new rosters every year, with one season having no bearing on the next. Aspects of football such as trading future draft picks or drafting early the next year due to a poor record the previous year are nonexistent in redraft leagues.
Redraft leagues require much less continual effort compared to keeper or dynasty leagues since they are over as soon as the season ends.
There are many reasons why it makes more sense to do a redraft league, especially if your fantasy football group is less hardcore. For starters, one bad trade will not screw you over for a long period of time. You may lose this year, but next season you can start fresh.
Another benefit is that the owners in your league can be flexible. In multiple year league, it is nearly impossible for a new member to join or for a current one to leave without creating a sort of redraft or expansion team.
The main disadvantages of redraft leagues is that winning and losing is more based on luck than other forms. Trades are less important and harder to execute similarly to real-life scenarios.
For a typical fan of fantasy football, however, redraft leagues are the best for casual fun and competition.