You should back-up your computer every few weeks (or as often as needed).
As soon as you suspect that your computer (or any other backup-able device) is too slow or "glitch-y" you should back-up your device before you lose any important files or data.
PREVENTING MALFUNCTION: → Always set your computer on a hard & flat surface. → Avoid downloading programs from unknown or non-trusted sources. → Avoid using your computer in a hot area. → Consider installing a virus/malware protection software on your computer.
Schedule and perform regular backups of your data. Installing antivirus software and updating it regularly is a good practice. You must also back up your data on a regular basis. This helps to prevent data losses due to unforeseen events. Such events may include a virus threat or computer malfunction.