When to carry a rosto
A Rostogol Stone protects your belongings in case of death, but the rosto then disappears from your inventory.
It primarily depends on the worth of your belongings, if carrying a rosto pays off. Furthermore, it depends on the probability with which you might be able to regain your death bag if you did not have a rosto.
The cost of a rosto is about 33kgc. Let say you have a 33% chance to regain your deathbag, then you should wear a rosto, if the stuff in your inventory (excluding the rosto) is worth more than
33kgc / 0.5 (because chance for dropping an item is 50%) /(1-0.33) which is the probability that you do not regain your DB -------------- 99kgc
If you have the Careful Guy Perk the second value is to be adjusted to 0.4, which yields a result that is 20% higher.
The chance for regaining your deathbag has to be adjusted. For example in invasions, there is additional risk:
- being bagjumped, since it is likely that other players are around when you die
- you cannot get back to the place because the invasion creatures keep killing you
- the bag disappears early because there are many drop bags on the map
Thus for invas, we could assume the worst case and calculate
33kgc / 0.5 (because chance for dropping an item is 50%) /(1-0) probability that you do not regain your DB is 0% -------------- 66kgc
as threshold limit when to carry a rosto.
In contrast, when you are with friends, it is very likely that they can save your DB, so we get
33kgc / 0.5 (because chance for dropping an item is 50%) /(1-1) probability that you do not regain your DB is 100% -------------- infinity
In other words, don't carry a rosto when you are with trustworthy friends.