Bought my last pair of headphones (HD 58X) like 4 years ago. They sound really good and don't require anything better to drive them than my cheap audio interface.

Because of the really good value you get from buying Sennheisers on Drop, I feel like I'd need to spend a ton of money to get a big upgrade in audio quality. Maybe if I have a money to burn one day I'll get a really expensive ($1000+) pair of headphones and a proper dac/amp to drive them, but I'm honestly content with my current setup. If it ain't broke don't fix it.