Macs are solid machines, but just like their owners they have a tendency to get lethargic as they age. Launching and switching programs takes longer, simple tasks become arduous, and the dreaded beach ball of doom appears more often than it did when your machine was new. The operating system just starts to feel crufty, and can get worse over time. I see these issues in my IT consulting business regularly.
You may be asking, why does this happen? There are many reasons, but some are more common than others. Sometimes your hard disk (or solid-state drive) gets too full and interferes with normal computer operations. Crashes or misbehaving programs can corrupt the disk directory or application cache files. Remnants from old software may still be running behind the scenes, or you don’t have enough RAM to deal with your OS and workflow.
Is there some sort of tune-up you can do to sort it out? Your tech always tells you to just reboot the computer, but there’s got to be more than that. The good news: Yes, there are some things you can do. And, perhaps, adopt some more-efficient computing practices for yourself along the way.