I would suggest keeping up to ten of these in inventory at all times, but no more. Ten will stack and take only one inventory slot. I also consider it one of the most disposable items in the game. If I need to free some space in inventory quickly to pick up a more valuable or quest-related item, they are the first item I sacrifice. When I have the space however, I do not waste them and use Igni whenever possible as sometimes the sign is just not an option, i.e. in town during daylight hours, whenever the area is considered "safe".
- Can be bought wherever jewellery and gifts can be bought.