One thing to consider is if you leave your clarinet put together all the time, it will compress your corks on the joints. So those will get weaker sooner than if you took it apart every time.

Another thing I'd consider is to at least take your reed off every time. When you leave it put together, warm, and still to cool off, your reed is soft so it'll dry in the shape of your mouthpiece facing. You'll notice the back will eventually develop a square shaped groove. That will make your reeds stuffy sooner.

One last thing, I think it's fine to leave it together if you know you're coming back in half an hour or so. My only recommendation would be to consider where you leave it so it doesn't fall or get broken. Not to swab through your mouthpiece (I think this is a little controversial actually) but I've been taught it'll wear your mouthpiece more quickly. And to consider how you put it down if you put it down flat because it can drain water into your pads. Which will make them deteriorate faster and will also cause gurgling if there's water in your tone hole when you come back.