Bike chain is one of the most important component in your bike too. Without it, you can’t ride your bike except for straight downhill.
Make sure you regularly check your chain with the chain tool like the picture below (there are many types out there but this one I find this very useful). It is recommended to change your chain when the reading is above 0.75 and below 1. Some may even do it before that to avoid damaging your bike chainrings or cassette.
So, don’t repeat the same mistake I did which I had 4000km (mostly are road mileage) on my bike and I have completely forgot to replace. Ends up it damaged my chainring which I have to replace the chainring. Fortunately, it didn’t damage the cassette.