I have set practice times, which IMHO is the best way to approach it.
4 times a week I practice for 2hrs 30mins in the evenings.
All other time is devoted to my partner and other things.
I work through different things, legato, picking, chordal, speed building and substitute some sessions now and again for other styles and devote 30mins to each section, then have 30mins just to play around with.
Any other free time I get, i.e. the missus goes out with friends/family etc or the odd quiet Sunday afternoon... I usually work on either building the guitar, learning/writing songs or updating the webpage
I stay in all week (I start work early)
and just go out to wind down at the weekends, usually with the missus and some friends.
I think it's definatley worth making the time to set yourself a structure/regime, or you find that you just widdle away aimlessley.