Being proactive can really pay off in your personal healthcare – it’s usually a lot cheaper to prevent a problem in the first place (or at least catch it early) than it is to try to fix it once it’s become a reality.
The same is true for your WordPress website. It may start with a few out of date plugins, no big deal (and it usually isn’t a big deal at first). Then a WordPress update comes out for a security issue, and it’s ignored. Eventually there are a lot of old plugins and you’re a few releases behind on WordPress core files. Maybe some little error shows up at the top of the admin area but doesn’t effect the look of the website, so you let it go…
It’s a slippery slope! The longer you wait to update, the more risk you’re taking.
If you put a lot of value on your WordPress site, don’t take the chance. Make sure everything stays up to date. And make sure that if a problem does happen, you’re covered, because you have a recent backup stored safely somewhere other than your hosting account. It’s much easier to recover a good backup than it is to clean up a hacked website – or to recreate months of work that disappears when a hard disk on a server goes bad and you discover there isn’t a fresh backup.