You could apply today's verse to your time on the internet, at school/uni/work, shopping... (you get the idea). Anything that involves coming across information and/or images. So what's the benchmark of 'worth'? Philippians 4:8 NLT says this: 'Fix your thoughts on what is true, and honourable, and right, and pure, and lovely, and admirable'. If you find you're taking in a lot of stuff that's at odds with what God wants, your impure-filter is under attack.
It's been the same since Adam and Eve, and the fact that the psalmist writes about his battle to keep his mind God-honouring is pretty telling. Put it like this: the world we live in has always gravitated toward selfishness. Even if you disconnect yourself completely from the world of technology, or never look at a billboard again, there'll always be reason to guard your mind. The answer's always been the same too: replace the world's influence with God's. 'How I long for Your precepts! In Your righteousness preserve my life' (Psalm 119:40, NIV). What does that look like, then? Actively inviting God to build a guard for your mind through Bible/ prayer time/ teaching podcasts, rather than passively hoping that the world won't pollute your mind.
Is it worth it? Yes. The freedom that comes with looking for what God wants above earthly desires will clear the mind-smog and take you much closer to the fullness God has for you.
So what now? Go to a park, a field or somewhere else that's a big, clear, outside space. Spend time walking there, praying for clarity of mind and purity.
Soulfood : Ruth 1:3-18, John 6:41-69