That's a tall plant! How big was it when you started 12/12?

The roots look great. i would do a full res change every 7-10 days. It's less work, saves you time and Nutes, and is just fine for the plant.

Is the height troublesome for you? in future grows are you going to try and control the height more? My only comment is that it looks like there's a bit of stretch.

Give us a quick rundown of your setup:

Room dimensions:
Light source:
hydro system:
Ventilation:
Strain:

Lookin good for your first grow!

skeet.