Unless you are using really long mudguards on your bike, a lot of crud gets flicked up from the front tyre and onto the chainring and chain.
This isn't particularly good for a drive system that needs the chain to be clean, for smooth gear changing and low drivetrain wear.
I came up with a small mod today, to help protect the front end of the chain and chainring from the stuff that gets flicked off the tyre.
It's not a particularly attractive solution and might still need a bit of tweaking to the position, but anything that helps keep the chain clean on a ride, is useful in my eyes.
I'm on the lookout for a molded piece of plastic, that will cover more of the front and look more aesthetically pleasing.