When we look at recent New York Mets bullpens, we find a lot of men who flamed out quickly. Many of these guys were either near the end of their career or at the beginning of a rather uneventful one.
Since the post-playoff 2016 season, it has been a major issue for the ball club. Finding relief help has been a futile effort. Whether via trade, free agency, or the minor leagues, the Mets have struggled with late-inning support.
In an attempt to set a standard, I would say a decent reliever gives a team a minimum of 40 innings and posts an ERA below 4.