No matter if you are a novice or an expert...scales and modes should be a part of your practice. Scales covers a lot of things:
1. Improves your music theory.
2. Good work out for your fingers, wrist and forearm.
3. Improves your timing.
4. Improves your accuracy.
5. Improves your dexterity and playing speed.
I always use at least 30mins just practicing scales and modes before I move onto other things and I have not deviated from that routine for over 12yrs. As far as how much time you want to spend practicing thats really down to you. 1 hour per day is good, but take one step at a time. Don't try and fit in too much. Concentrate on one thing until you nail it and keep practicing it over and over again until you feel confident then move onto something else. It takes time to become a competent musician no matter how many hours you dedicate to practicing, but keeping to a strict routine will help you ten fold! If you personally practice 1 hour a day that sums up to 28hrs in a month...that's more hours than I practice per month! Keep it up! You will get to where you want to go before you know it! The devil will try to slow you down, but he can't hit a moving target!