Congrats on getting here and getting "fixed". Everyone is different. The rule of thumb is not really a rule at all. Use two, one or no crutches as necessary to get around. Basically, the conventional wisdom is to use what you need to keep from limping, or at least limping uncomfortably. Moving to one crutch can happen pretty quickly if you don't try to move super fast, and don't be afraid to use more as you get tired or have more pain.
You will hear a common chant on the site and its true...its not a race, so you are the best judge as to when, and how fast, you recover. If you rush things you are probably more at risk than if you are too conservative so don't feel pressured to make progress on any sort of schedule.
Incisions and the associated pain are individual too. Mine begain to "itch" at around 3 weeks, so I rubbed and rubbed. At 4-5 weeks I started using a foam roller to massage the area. Not much at first (because it was too tender) but more as the area could tolerate. Seems to help minimize the discomfort of the scar tissue. Some have longer incisions, more muscle that was cut, etc. etc., so again, you are the best to evaluate what you need. If the incision pain was keeping me up, I would try tylenol or something else to get the rest you need to keep the recovery going. No fun being tired and sore, so eliminate the tired.
Best of luck on your recovery. You'll get lots of support and opinions here...
Curt