In these busy times, many people believe, if it ain't broken, don't fix it. I believe that too, but it isn't an excuse for not taking action to maintain your database servers and be sure that nothing will break.
Database maintenance is about making your database run smoothly.
Monitoring systems are not a substitute for good planning. They alert you to unplanned situations that need attention. The more unplanned things you respond to, the greater the chance that you will need to respond to multiple emergencies at once. And when that happens, something will break. Ultimately, that is your fault. If you wish to take your responsibilities seriously, you should plan ahead.