OOP is still a good model for systems where most objects are long-lived, local, mutation latency is low, and the number of objects is reasonable. Like GUIs and

OOP is still a good model for systems where most objects are long-lived, local, mutation latency is low, and the number of objects is reasonable. Like GUIs and simulations. (Not coincidentally those are the domains where OO was introduced.) It’s not a good fit for systems that respond to short-lived requests. If your objects’ lifetimes are never longer than a HTTP request, you shouldn’t be using OOP. It’s not the right model! (I call this “kamikaze OOP”: you build a complex piece of machinery in memory and crash it down the next instant.) At the other end of the spectrum, if your real-time system deals with potentially huge amounts of objects, then OO isn’t a good fit either because it doesn’t easily let you optimize memory layouts so you could loop over all that data. Something like ECS (entity component system) is probably a better fit.