about whether your bullpen can do the job your starter is already doing well because your bench bat is worth 150 more points than that pitcher, and a hit gives you the lead.
Even if you get that hit and that lead, can your pen hold it?
Do you trust the rest of your offense to get that lead later in the game if you give up that points advantage, and leave your starter in?
Is leaving him in worth risking him getting lit up due to an increasing pitch count?
This has nothing to do with a double switch.