Most of my current applications have been opened since the computer booted (11 days ago). Where I'm drawing the line is wasting resources and time while I'm using them. As you said, mostly about user interactions and scrolling because UI is bound to IO for some reason. I remember all the big software taking time to startup (Adobe's, Autodesk's, even Microsoft Office's), but once they do, it was pretty smooth unless you launch that computer/gpu intensive operation. But now, things like Slack causes the computer fan to scream.