I used to repair computers, and whatever I went to fix, I always asked them about backing up their data. I didn't sell drives, so it was a service of free advice. They call me when things go wrong, and it's the one thing I can't help them with is the drive is completely dead. I've seen enough tears from people who have not backed up.
Always have a backup of some sort if you value the data. Automatic backup is best. If you can make an offline backup of the most important data (like pictures of your kid), then do it. Google drive is a free option for a relatively small amount of data, like a folder full of important documents.
While some HDs last for years, the failure rate of drives is 6% to 8% per year.