MLS averages approximately 2.7-3.0 goals per match across the league, making the standard 2.5 line a tight proposition. Matches involving attacking teams or poor defenses may see the line pushed to 3.0 or 3.5.
Factors that influence the over/under include weather (heat can lead to tired defending), playing surface, team form, and tactical matchups. Historical head-to-head data can also inform over/under decisions.