Depends on the conditions, and Captain, Management game plan. If it's a cloudy weather, green lush grass on pitch then captains prefer to win toss and bowl first to take advantage of the fresh pitch and early swing. Pitches in England are most likely to fit this criteria.

If it's dry pitch with patches, and might spin later then teams prefer to win toss, put runs on the board and defend with good quality spinners. Pitches in India and Sri Lanka most likely to fit this criteria.