I treat playing and practicing separately.
If I am playing then I may well play on and off for a couple of hours time permitting. If I am practicing then usually I would practice for half hour with a short break then again for half hour. I might continue this all day but usually work/family/other commitments makes playing for a lengthy time impossible.
I don't necessarily find practicing a chore. It is of course not so fun as playing however, usually the next day. when you can see the results of your practicing paying off, the sense of satisfaction is well worth it!
I don't usually sit there an run through technical exercises or scales and modes any longer. I tend to be trying to work slowly on a fast lick or a whole song.
For example, of late I have been spending a lot of time trying to learn "A Song for Life" by Eric Johnson. I am currently practicing this for at least half hour a day. Yesterday I managed to practice for around two hours in between other playing! This sort of time to myself rarely occurs these days!