You manage it. Long hours don't always come with a development job, but they can. In my particular case, I'm not the best at managing time, so I may work slow one day, and the next day, double up on my hours. To some outsiders this may look like a taxing job, but it really isn't. It's just my terrible time management skills.
Because of this, I do occasionally find difficulties investing in circular activities such as higher-education as well, but, like anything else in your life, if you wanna do it, than just do it. I can almost assure you that you have the available time in a given week to complete course work for a part-time schedule. Many people simply don't want to acknowledge how much time they waste in a day, sometimes knowingly, sometimes unintentionally.
If you could, try taking an objective look back at how you spent the last week. How much of it was spent on short-term feel-good activities? I.e. TV, Games, Bars, Drinking, Parties? I'd wager most people have plenty of available time in their schedule, it just becomes a question of what you're willing to sacrifice for it.
Now, I'm not saying never do anything you enjoy doing. Or snuff your family/friend obligations. That's a terrible way to live, and for some people, that's simply not an option. But there's always a happy, healthy medium to be found.