There are two types of remotes for the Roku. The standard IR (infrared) version, and the wireless version. Obviously, the remote is an essential part of controlling the Roku which means it needs to work reliably.
Remote stops working.
Whenever experiencing issues with your remote; the very first thing that you should try is to change the batteries. Doing this is quick and easy and will save you a bunch of time if it turns out to be the issue.
If you have replaced the batteries with new ones, then you should next try unplugging the Roku and plugging it back in. Sometimes, what might seem like a problem with the remote is actually a problem with the Roku device itself. If you have lots of channels installed, the Roku might be low on memory which can cause it to lag and operate sluggishly. This happens a lot on older models where you will push a button on the Roku and it will then happen a couple of seconds later. The more buttons you push, the worse it gets as it tries to keep up.
Another thing to try is to re-pair your remote. This step applies only to the advanced remotes. To re-pair your Roku remote, you need to remove the battery cover on the back and press the small round purple button. Give it 10-15 seconds and then try the remote again.
In a worse case scenario, you will need to contact Roku customer support. If you are still covered under warranty, they will most likely send you a replacement remote to try out.
If you have an iPhone, Android, or Windows smart phone, you can install a Roku remote control app which will let you control any Roku devices that are connected to your home network. There are several different versions to install, however the official Roku ones are the best choice.