Does the sealant harden after a not very long period of time? How do you change the tyre, will the rim be covered in shite? Also is there some faff involving having to put pressure in rapidly when first installing them?
So what happens when the sealant hardens, you have to change the tyre?
If you've been riding rather than storing your bike, it forms a thin layer on the interior surface of the tyre. You keep adding new batches until the tread wears out, which will probably only be once or twice if you ride a lot.
Yes, yes and yes. Still worth it.