I work full time, sometimes work longer than 8 hr/day, but I still manage to make time to practice at least 1 hr/day and at least 2-3 hr/day on the weekends. For me, playing piano is like a break from my job (and I work as a chemist in the lab) so I treat it as play time. I'm working on a couple of pieces, trying to get back to the level where I was at before. I had played heaps when I was in high school, was even the accompanist for my school choir but stopped when I got to college because I didn't have access to a piano, and didn't like how mechanical I sounded whenever I got back home to my piano. I only have a little (66-key) Yamaha keyboard now, hopefully one of these days I'll be able to afford a good piano so I could go back to practicing the music I used to play (was working on Csardas and Chopin's Fantasie Impromptu before I stopped playing so many years ago).
But before having gone into that tangent ... I feel like I have no energy myself when I get home, but after a good meal and a good rest, I feel like I have the energy to get at the keyboard and work on my pieces, and sometimes if I'm not interrupted by phone calls or friends dropping by, I lose track of time and before I know it, it's bedtime already. So I guess it depends on you, how much energy you have at the end of the working day if you feel you're able to put your attention to your practice.
