The answer to this question typically depends on the issues experiences.
However, if you know roots are regularly entering your drain lines, it is likely a good idea to clear the lines once a year to avoid blockage.
If you have a sink that frequently slows down from hair blockage, it would be a good idea to address the problem before the drain is clogged.
You can set a recurring reminder to clear your drains based on how frequently you experience issues. This is good preventative maintenance.