If a circuit only needs 12/2 wire, is it okay to run 12/3 and leave the red disconnected and wire nutted at the outlet and in the panel.
The reasoning is to have more options in the future or if one wire is bad after everything is done, you have a spare wire to work with. Is there any code violation against this?
I ask the question because if someone is rewiring their entire house, it probably makes sense to run all 12/3 instead of 12/2 because it is the same amount of work and only costs a little more money. If there ever is a problem in the future with one of the wires(drywaller screws through one by accident or whatever) you have a spare without the need to fish through. Or if someone swaps a ceiling fan for a light fixture and they want to control the fan and light with 2 different switches, the wires are there.
For an entire house, the cost would be much higher than you think. In addition, you will have to preplan the box sizes in order to stay compliant with conductor fill for the additional wires.
Also, if the jacket of NM cable is puncture severely enough to cause one of the wires to break then the whole thing needs to be replaced or a junction box if it is an accessible area.
I am all for running 14/3 to fixtures from switches as long as you also preplan by installing ceiling fan rated boxes just in case.
Buy 12/3 for the countertop circuits, use a ganged 20amp breaker. For the dishwasher/waste disposal, run a 20amp circuit, but break the tab between the two receptacles. Have one receptacle switched for the waste disposal.
Consider running 6/4g for the range, electric is nice for the oven. Run a separate 20amp for the range hood/microwave. You're on your own for lighting, but I'm hoping to try out the Cree CR6 LED cans soon.