There is a certain pace to most law practices, but it might take you some time to learn it. Is your practice linked to a local court calendar? Then it's easier to schedule vacations around the court. Will you be on calls/video conferences with global clients in time zones all around the world? If so, perhaps you can start of your day early with Asia and then end it early to meet up with friends. Will you be traveling to clients (around your state, across the US or all over the globe)? If so, maybe you can add a weekend to that business trip to visit your buddies in that area. (MOST companies/firms will allow you to do so provided you pay for your own hotel or any increased travel cost - like plane or train tickets.) Also, some aspects of law practice encourage socialization - especially business development at law firms (which is a fancy way of saying "finding & landing new clients"). Whether that is within your existing social circle or expanding it, you may be surprised at the time you spend socializing for work.
To be honest, most attorneys put in lots of hours - it's a requirement at most large firms to do so to maintain good performance reviews/stay on partnership track. But even roles at small firms, in-house and as govnt attorneys tend to be demanding jobs that are rarely just 9AM-5PM. In addition to working for your clients, you have to maintain your skills with Continuing Legal Education classes (specific hour requirements vary by state), volunteer your time with Pro Bono legal work, and -- typically -- conduct some sorts of business responsibilities, too (e.g., developing new clients at a firm, management/review/HR issues for the team of lawyers who report to you). Some types of practices or a part-time practice may allow attorneys to better can carve out routines. Once you really get into your role, you'll notice the ebbs and flows of your unique practice, when things get busy (e.g., end of quarter for in-house counsel or fiscal year in govnt) and when there is more flexibility (holiday weeks when court isn't in session for litigators).
Desiree recommends the following next steps: