Just what it says really. I’ve just set my cotic soul up as a 1×9 after having a double and bash for a while. I’ve been for a quick blast down some stairs and rooted descents with no sign of the chain coming off. I was going to buy a cheap chain guide from superstar but is it really necessary?
I’ve used pretty much every device going over the past five years with varying amounts of success. I think the above posts maybe demonstrate is that some, cirumstances and setup require them to have a device whereas for others it’s not neccessary.
I’d say hold fire and ride without for a while (but make sure there’s plenty of protection / helitape on the vunerable parts of your frame: BB and chainstay). If you find you’re droppping your chain, maybe go for the superstar device (cheap but they’re as good as any I’ve tried). You might find you’re one of lucky ones and don’t drop your chain.