Should I replace regular light switches with smart switches?

It depends on what you need. If you just want the basics - turning the light on and off - regular switches do the job fine and don't require batteries or syncing with an app. But if you often forget to turn off the lights, want to control them from your phone, or set up automation (like turning them on when you get home in the evening), then smart switches make sense - though you'll have to figure out the installation and find a good model so you don't run into signal issues.