It's extremely difficult to practice correctly, no matter who you are. I voted for "some of the time." Its easy to get lost or to beat balls or to think your'e doing something right when in fact you aren't.
My ideal way to practice consists of the following prerequisites IMO:
1) Grass range
2) Your very qualified instructor present
3) Trackman hooked up so you can see your actual numbers. Changes become even clearer this way. You aren't necessarily trying to improve those numbers whenever you practice obviously, but they can definitely be useful as hell from time to time.
4) A high speed camera at the ready to show you whatever changes you are making and that feel isn't real
5) An understanding of when to hit slower tempo, half shots to hit a specific piece in the golf swing that you and your teacher want improved or fixed.
Then you learn what it feels like to hit that piece and you can practice by yourself. Take notes and maybe get a printed out before and after photo of this change you are making, so the image can really sink in. Discussions with your instructor about it can be helpful in cementing the "why" factor as well if you are skeptical over a suggestion he makes.
I use evolvr, so it's obviously not as good as the above. It keeps me on a path, but by myself, alone out there, its easy to stray from what I'm there to do. Discipline and patience is key. Evolvr is a good way to go if you don't have a good instructor near you. I recommend it.
My best practice sessions are when I stick to what the hell my teacher tells me to do, I slow down to hit that piece, and I practice it diligently. I wish I was smart enough to stick to this every time.
Tangent: 100 years from now golf lessons will be able to be conducted through hologram platforms where you can get in touch with any instructor in the world if they also have a hologram platform. Trackman numbers and slow motion holographic swings that can be viewed 3-dimensionally by the teacher will be the future... Sorry, I was dreaming for a second there. Carry on, guys.