for D.IV, it's less important to have 8's and 9's in game shape, but the standard level for most players on the opposition is at worst a 5 or 6 from players that enter the game. So there are advantages to running guys out there for somewhere in the upper 50's to low 60's every week in an attempt to get optimum game shape. However, sometimes you also have to put your star player out there as some teams at this level (in the US at least) have one 40k player and a bunch of 6k or less salaries. So sometimes you need that guy to go 35-40 minutes a game two games in a row.